Flexible circuit board, special-shaped double faced adhesive tape and electronic equipment

Abstract

The invention provides a flexible circuit board, a special-shaped double-faced adhesive tape and electronic equipment. Specifically, the flexible circuit board comprises a circuit layer, a first covering layer and a first electromagnetic shielding layer, wherein the first covering layer and the first electromagnetic shielding layer are sequentially arranged on the circuit layer; the first covering layer comprises at least one window, and the line layer is connected with the first electromagnetic shielding layer at the position of the window; the area of the projection of the window in the direction perpendicular to the line layer is 1-30 mm < 2 >. The virtual connection area of the flexible circuit board is reduced by using the windowing area, so that the pressing abnormal sound can be eliminated.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a flexible circuit board, a special-shaped double-sided adhesive tape and an electronic device. Background Art

[0002] With the development of technology, flexible circuit boards are increasingly being used in mobile phones and other electronic devices, such as curved screen phones and foldable screen phones. However, electronic devices using flexible circuit boards currently have the problem of abnormal sound when pressed. Summary of the invention

[0003] In view of this, the purpose of the present disclosure is to provide a flexible circuit board, a special-shaped double-sided adhesive tape and an electronic device.

[0004] Based on the above purpose, the present disclosure provides a flexible circuit board, which includes: a circuit layer, and a first covering layer and a first electromagnetic shielding layer sequentially arranged on the circuit layer; wherein,

[0005] The first covering layer includes at least one opening, and the circuit layer is connected to the first electromagnetic shielding layer at the position of the opening; the projection area of ​​the opening in a direction perpendicular to the circuit layer is 1 to 30 mm 2 .

[0006] Based on the same inventive concept, the embodiment of the present disclosure also provides a special-shaped double-sided adhesive tape, including a first body layer, a second body layer, a first protective film, a second protective film and a third protective film; wherein,

[0007] The second body layer is located on the first body layer and the area of ​​the second body layer is smaller than that of the first body layer;

[0008] The first protective film is disposed on a side of the second body layer away from the first body layer; the third protective film is disposed on a side of the first body layer away from the second body layer;

[0009] The second protection film is located around the second body layer and between the first body layer and the first protection film.

[0010] Based on the same inventive concept, an embodiment of the present disclosure further provides an electronic device, comprising any of the flexible circuit boards described above.

[0011] As can be seen from the above, the present disclosure provides a flexible circuit board, a special-shaped double-sided adhesive tape and an electronic device, wherein the flexible circuit board comprises: a circuit layer and a first covering layer and a first electromagnetic shielding layer sequentially arranged on the circuit layer; the first covering layer comprises at least one opening, and the circuit layer is connected to the first electromagnetic shielding layer at the position of the opening; the area of ​​the projection of the opening in a direction perpendicular to the circuit layer is 1 to 30 mm2 , using a smaller window area to reduce the virtual connection area of ​​the flexible circuit board, thereby helping to eliminate abnormal pressing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the present disclosure or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings, the thickness and shape of some layers and regions may be exaggerated for better understanding and ease of description.

[0013] Figure 1A A schematic diagram showing the structure of a display module provided in the related art is shown;

[0014] Figure 1B Show Figure 1A A schematic diagram of the structure of the display module from another perspective;

[0015] Figure 2A Shown along Figure 1B A cross-sectional view of a portion of the structure of the flexible circuit board taken along the center line AA;

[0016] Figure 2B Shown along Figure 1B A cross-sectional view of a partial structure of another flexible circuit board taken along the center line AA;

[0017] Figure 3A A schematic diagram of the structure of a flexible circuit board provided by an embodiment of the present disclosure is shown;

[0018] Figure 3B A schematic diagram showing the shape of a window provided by an embodiment of the present disclosure is shown;

[0019] Figure 3C A schematic diagram showing the shape of another window provided by an embodiment of the present disclosure;

[0020] Figure 3D A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0021] Figure 3E A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0022] Figure 3F A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0023] Figure 3G Show Figure 3F The enlarged view of the dashed box in ;

[0024] Figure 3H A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0025] Fig. 3I A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0026] Figure 3J A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown;

[0027] Figure 4 A schematic structural diagram of a special-shaped double-sided adhesive tape provided in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connecting" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. Even if it is not clearly stated, the components are interpreted as including a normal error range. When an element or layer is set "on" another element or layer, another layer or element can be directly inserted on the other element or between them.

[0030] Figure 1A A schematic structural diagram of a display module provided in the related art is shown. Figure 1B Show Figure 1A A schematic diagram of the structure of the display module from another perspective. Figure 1A and Figure 1BAs shown, the display module 100 includes a display panel and a flexible printed circuit board 103 (Flexible Printed Circuit Board, FPC board for short). The display panel can be formed in a rectangular plane, the rectangular plane has a long side in a first direction (y-axis direction) and a short side in a second direction (x-axis direction) intersecting the first direction (y-axis direction), and the display panel has a certain thickness in a third direction (z-axis direction) perpendicular to the rectangular plane.

[0031] Furthermore, the display panel includes a display area 101 and a non-display area 104, and the non-display area 104 includes a binding area 1041. The flexible circuit board 103 is fixed on the binding area 1041 of the display panel, and the binding area 1041 and the flexible circuit board 103 are bent and bonded to the side of the main body 105 away from the display panel, thereby constraining the binding area 1041, reducing the possibility of impact and repeated bending before the terminal product is assembled, and reducing the risk of failure of the flexible circuit board 103 due to impact and repeated bending.

[0032] In order to avoid electromagnetic interference and ensure that the electromagnetic shielding layer in the flexible circuit board 103 can achieve a better effect, part of the structural layers of the flexible circuit board 103 include windows 102 . Figure 2A Shown along Figure 1B A cross-sectional view of a portion of the structure of the flexible circuit board 200 taken along the center line AA; Figure 2B Shown along Figure 1B A cross-sectional view of a portion of the structure of another flexible circuit board taken along the center line AA. Figure 2A and Figure 2B As shown, the flexible circuit board 200 includes a circuit layer 201, a first cover layer 202 (Cover Layer), a second cover layer 204, a first electromagnetic shielding layer 203, a second electromagnetic shielding layer 205, and a first adhesive layer 209. The first cover layer 202, the first electromagnetic shielding layer 203, and the first adhesive layer 209 are sequentially arranged on a side of the circuit layer 201 close to the main body 105; the second cover layer 204 and the second electromagnetic shielding layer 205 are sequentially arranged on a side of the circuit layer 201 away from the main body 105.

[0033] Optionally, the first cover layer 202 is fixed on the circuit layer 201 through a first adhesive layer 206 , and the second cover layer 204 is fixed on the circuit layer 201 through a second adhesive layer 207 .

[0034] Exemplarily, the material of the first covering layer 202 and the second covering layer 204 may be polyimide (PI for short); exemplary, the first adhesive layer 206 and the second adhesive layer 207 may be pressure sensitive adhesive (PSA for short).

[0035] Exemplarily, the thickness of the first covering layer 202 and the first adhesive layer 206 can be 10 to 30 μm, respectively. For example, the thickness of the first covering layer 202 is 10 μm, 12.5 μm, 15 μm, 20 μm, 22.5 μm, 26 μm or 30 μm, and the thickness of the first adhesive layer 206 is 10 μm, 11 μm, 13.5 μm, 16 μm, 20 μm, 25 μm or 30 μm, etc.

[0036] Furthermore, the first cover layer 202 and the first adhesive layer 206 are provided with a window 208 (refer to Figure 2A ), the first electromagnetic shielding layer 203 is bent at the position of the window 208 to connect the circuit layer 201 (reference Figure 2B ), such a structure is conducive to improving the electromagnetic shielding effect. However, the bending of the first electromagnetic shielding layer 203 at the window 208 inevitably produces a step h. Due to the existence of the step h, when the user presses the electronic product, the first adhesive layer 209 and the first electromagnetic shielding layer 203 will be bonded-disconnected-bonded, resulting in local abnormal sounds, affecting the user experience.

[0037] In view of this, the embodiments of the present disclosure provide a flexible circuit board, a special-shaped double-sided adhesive tape and an electronic device, wherein the flexible circuit board comprises: a circuit layer and a first covering layer and a first electromagnetic shielding layer sequentially arranged on the circuit layer; the first covering layer comprises at least one opening, and the circuit layer is connected to the first electromagnetic shielding layer at the position of the opening; the area of ​​the projection of the opening in a direction perpendicular to the circuit layer is 1 to 30 mm 2 , using a smaller window area to reduce the virtual connection area of ​​the flexible circuit board, thereby helping to eliminate abnormal pressing noise.

[0038] Figure 3A A schematic structural diagram of a flexible circuit board 300 provided in an embodiment of the present disclosure is shown; Figure 3D FIG. 2 is a schematic diagram showing a structure of another flexible circuit board provided by an embodiment of the present disclosure. Figure 3A and Figure 3D As shown, the flexible circuit board 300 includes a circuit layer 301. A second covering layer 304 and a second electromagnetic shielding layer 305 are provided on a side of the circuit layer 301 away from the main body 311. A first covering layer 302, a first electromagnetic shielding layer 303 and a first adhesive layer 309 are provided on a side of the circuit layer 301 close to the main body 311. Optionally, the first covering layer 302 is fixed on the circuit layer 301 through a first adhesive layer 306, and the second covering layer 304 is fixed on the circuit layer 301 through a second adhesive layer 307.

[0039] Furthermore, the first covering layer 302 and the first adhesive layer 306 include windows; the projection area of ​​the windows on the circuit layer 301 is 1 to 30 mm.2 , that is, the projection area of ​​the window in the z-axis direction is 1 to 30 mm 2 , for example 1mm 2 , 2mm 2 , 3.5mm 2 , 5mm 2 , 7mm 2 , 8mm 2 、9.5mm 2 , 10mm 2 , 15.5mm 2 , 20mm 2 , 21.5mm 2 , 25.5mm 2 、27mm 2 or 30mm 2 Etc. If the projected area is less than 1mm 2 , it is not convenient to connect the first electromagnetic shielding layer 303 and the circuit layer 301, and the resistance between the two is large; if the projected area is greater than 30mm 2 , it is easy to produce abnormal pressing noise.

[0040] Optionally, the projected area is 1 to 8 mm 2 , 2~10mm 2 , 4~10mm 2 , 1~6mm 2 , 3~7mm 2 , 13~30mm 2 , 1~20mm 2 , 20~30mm 2 , 16~25mm 2 or 5~25mm 2 wait.

[0041] Such a structure can ensure that the resistance between the first electromagnetic shielding layer 303 and the circuit layer 301 is small, for example, <0.5 ohms, which plays an electromagnetic shielding role. At the same time, such a small-area window can reduce the virtual connection area between the first glue layer 309 and the first electromagnetic shielding layer 303, thereby helping to eliminate abnormal pressing noise.

[0042] In some embodiments, the projection shape of the window on the z-axis can be rectangular, circular, or elliptical.

[0043] In some alternative embodiments, the projection shape of the window on the z-axis is a rectangle with an aspect ratio ≥ 2, and the virtual connection area is effectively reduced, which helps to eliminate abnormal noise. It should be noted that the rectangle here can be a rounded rectangle, and the present disclosure does not limit this. Figure 3B A schematic diagram showing the shape of a window provided by an embodiment of the present disclosure is shown; Figure 3C FIG. 2 shows another schematic diagram of a window shape provided by an embodiment of the present disclosure. Figure 3B and Figure 3C As shown, Figure 3B The area of ​​the rectangle in Figure 3C The area of ​​the square in is the same (corresponding to the area of ​​the window on the side away from the circuit layer 301, which is also the projection area), that is, l1×l2=l4 2 Considering that the window is tilted at a certain angle in the z-axis direction, under the condition of the same angle, the bottom area of ​​the window is (l1-l3)×(l2-l3)<(l4-l3) 2 , that is, the area of ​​the window on the side close to the circuit layer 301. It can be seen that the rectangular shape is more helpful in reducing the area of ​​the window on the side close to the circuit layer 301, and is more helpful in eliminating abnormal noise.

[0044] In some optional embodiments, such as Figure 3A As shown, the projection of the window in the direction perpendicular to the circuit layer 301 is located at an overlapping area of ​​1 to 5 mm with the projection of the first adhesive layer 306 in the direction perpendicular to the circuit layer 301. 2 , for example 1mm 2 , 2.5mm 2 , 3.4mm 2 or 5mm 2 The first adhesive layer 306 completely or partially covers the window. The overlapping area is 1-5 mm 2 It is small enough that the first adhesive layer 306 is difficult to contact the first electromagnetic shielding layer 303 in the window, which can effectively avoid virtual contact between the first adhesive layer 306 and the first electromagnetic shielding layer 303, thereby achieving the technical effect of eliminating abnormal noise.

[0045] In some optional embodiments, such as Figure 3D As shown, the projection area of ​​the window on the circuit layer 301 is 5 to 30 mm 2 , the projection of the first glue layer 306 on the circuit layer 301 and the projection of the window on the circuit layer 301 do not overlap, and the distance a1 between the two is ≥ 0.2mm, such as 0.2mm, 0.5mm, 1.0mm, etc. Such a structure can fundamentally avoid the first glue layer 306 and the first electromagnetic shielding layer 303 in the window from contacting each other, and can effectively avoid the first glue layer 306 and the first electromagnetic shielding layer 303 from virtual contact, thereby achieving the technical effect of eliminating abnormal noise.

[0046] In addition to the above embodiment, the embodiment of the present disclosure further exemplarily illustrates the parameters of the first adhesive layer 306 .

[0047] In some embodiments, the thickness of the first adhesive layer 306 is 0.05-0.20 mm, such as 0.05 mm, 0.08 mm, 0.10 mm, 0.12 mm, 0.15 mm, 0.20 mm, etc. If the thickness of the first adhesive layer 306 is less than 0.05 mm, the gap between the first adhesive layer 306 and the step h is small, which limits the absorption capacity of the first adhesive layer 306; if the thickness of the first adhesive layer 306 is greater than 0.20 mm, not only is the adhesive material wasted, but it is also not conducive to the preparation of thin and light products.

[0048] Optionally, the thickness of the first adhesive layer 306 is 0.05-0.10 mm, 0.05-0.15 mm, 0.07-0.15 mm, or 0.10-0.20 mm.

[0049] By increasing the thickness of the first adhesive layer 306 and increasing the gap between the thickness of the first adhesive layer 306 and the step h, the ratio of the step relative to the first adhesive layer 306 is reduced, thereby improving the absorption capacity of the first adhesive layer 306 for the step h. In addition, the thicker first adhesive layer 306 can also increase the viscosity and reduce the risk of interface debonding.

[0050] In some embodiments, the first adhesive layer 306 is a double-sided adhesive containing a substrate; the substrate thickness of the double-sided adhesive containing a substrate is less than 1 / 10 of the total thickness; the elastic modulus of the substrate of the double-sided adhesive containing a substrate is less than 2 GPa, such as 1 GPa, 0.5 GPa, etc. By limiting the thickness and elastic modulus of the substrate, the flexibility and adhesion of the first adhesive layer 306 can be increased, thereby reducing false connections and reducing the risk of abnormal noise.

[0051] In some embodiments, the first adhesive layer 306 is a double-sided adhesive without a substrate, and the elastic modulus of the double-sided adhesive without a substrate is 10KPa to 50MPa, such as 10KPa, 200KPa, 500KPa, 900KPa, 10MPa, 50MPa, etc. Optionally, the elastic modulus of the double-sided adhesive without a substrate is 10KPa to 20MPa, 10KPa to 40MPa, 20KPa to 50MPa or 30KPa to 30MPa, etc. Such a setting can ensure that the first adhesive layer 306 has greater tensile and shear properties, reduce the generation of abnormal noise, and also reduce the risk of the first adhesive layer 306 being debonded as a whole due to the substrate interface.

[0052] The step introduced by the window opening not only brings about abnormal noise problems, but also reduces the bonding area to a certain extent, thereby weakening the bonding reliability; in addition, the existence of the step inevitably causes the first adhesive layer 309 to cause the film material thereon to move and deform when pressed, thereby increasing the appearance of the film print and causing poor appearance. Figure 3E A schematic diagram showing the structure of another flexible circuit board provided by an embodiment of the present disclosure is shown; Figure 3F , Figure 3H , Fig. 3I , Figure 3J Schematic diagrams of the structure of another flexible circuit board provided by the embodiment of the present disclosure are shown respectively. Figure 3E to Figure 3J As shown, the flexible circuit board 300 can also be provided with a filling structure 310 in the opening. The filling structure 310 can completely eliminate the step difference, help to fundamentally solve the abnormal sound problem, ensure the bonding area and improve the bonding strength, and improve the poor appearance.

[0053] The technical solution of the filling structure 310 is particularly suitable for small-sized electronic devices with limited bonding areas, and can effectively ensure the bonding area and improve product quality.

[0054] In some embodiments, Figure 3E to Figure 3J As shown, the height H2 of the filling structure 310 perpendicular to the circuit layer 301 is less than the height H1 of the opening perpendicular to the circuit layer 301. Such a technical solution can prevent the flexible circuit board from bulging near the main body 311 and affecting the bonding performance.

[0055] In some embodiments, Figure 3E As shown, the material of the filling structure 310 is a conductive material, such as conductive cloth, conductive rubber or conductive silicone, etc. The filling structure 310 is located between the first electromagnetic shielding layer 303 and the circuit layer 301, and the first electromagnetic shielding layer 303 is connected to the circuit layer 301 through the filling structure 310. It should be noted that the filling structure 310 is arranged at the opening before the first electromagnetic shielding layer 303 is formed.

[0056] In some alternative embodiments, such as Figure 3F , Figure 3H , Fig. 3I and Figure 3J As shown, the material of the filling structure 310 is an insulating material, the first electromagnetic shielding layer 303 includes a bending structure located in the window, and the filling structure 310 is located on the side of the bending structure away from the circuit layer 301, so that the first electromagnetic shielding layer 303 uses the bending structure to connect to the circuit layer 301.

[0057] like Figure 3F As shown, the filling structure 310 includes polyimide or polyethylene terephthalate with adhesive on one side. It should be noted that the filling structure 310 formed of polyimide or polyethylene terephthalate has adhesive on at least one side for fixing the filling structure 310 on the bending structure of the first electromagnetic shielding layer 303 .

[0058] like Figure 3HAs shown, the material of the filling structure 310 can be double-sided adhesive. Exemplarily, the elastic modulus of the double-sided adhesive is ≥ 100MPa, such as 100MPa, 150MPa, 200MPa, etc. Exemplarily, the double-sided adhesive includes a substrate 313 and adhesive layers 312 located on both sides of the substrate 313. Such double-sided adhesive can ensure that the filling structure 310 is less deformed when subjected to pressure, thereby reducing the deformation of the first adhesive layer 309 when pressed, which helps to reduce abnormal noise and improve poor appearance.

[0059] Figure 3G Show Figure 3F Here we use Figure 3G As an example, the shape of the filling structure 310 is described. The filling structure 310 includes a first surface close to the circuit layer 301, a second surface away from the circuit layer 301, and a side surface between the first surface and perpendicular to the circuit layer 301; in the direction of the first surface, the distance a2 between the side surface and the first electromagnetic shielding layer 303 is greater than zero. Such a setting can prevent the filling structure 310 from damaging the first electromagnetic shielding layer 303.

[0060] The shape of the filling structure 310 can also be as follows Fig. 3I Reference Fig. 3I The filling structure 310 includes a first surface close to the circuit layer 301, a second surface away from the circuit layer 301, and a side surface between the first surface and inclined relative to the circuit layer 301. Optionally, the filling structure 310 can be formed by a liquid curing material, such as ink, glue, etc. Optionally, the elastic modulus of the filling structure is 200MPa to 3GPa, such as 200MPa, 500MPa, 800MPa, 1GPa, 2GPa, 3GPa, etc. Such a double-sided adhesive can ensure that the filling structure 310 is less deformed when subjected to pressure, thereby reducing the deformation of the first adhesive layer 309 when pressed, which helps to reduce abnormal noise and improve poor appearance.

[0061] Next Figure 3G ,by Figure 3G The bonding force of multiple contact surfaces is described by taking the example of the bonding force of multiple contact surfaces. The difference in bonding force between the contact surface A1 between the filling structure 310 and the first electromagnetic shielding layer 303, the contact surface A2 between the filling structure 310 and the first adhesive layer 309, and the contact surface A3 between the first adhesive layer 309 and the main body 311 is ≤10%. By limiting the bonding force difference of the three contact surfaces, the bonding force of the three contact surfaces is ensured to be as balanced as possible, which helps to prevent tearing of a certain interface.

[0062] In some embodiments, Figure 3J As shown, the filling structure 310 and the first adhesive layer 309 are formed by special-shaped double-sided adhesive tape. Figure 4 FIG. 2 is a schematic diagram showing the structure of a special-shaped double-sided adhesive provided by an embodiment of the present disclosure. Figure 4As shown, the special-shaped double-sided adhesive tape 400 includes a first body layer 4011 and a second body layer 4012 located on the first body layer 4011, and the size of the second body layer 4012 corresponds to the size of the filling structure 310. Here, the special-shaped double-sided adhesive tape can be in the form of double-layer double-sided adhesive tape stacking, 3D printing, die-cutting and bonding, etc. With the special-shaped double-sided adhesive tape, the filling structure 310 and the first adhesive layer 309 are an integrated structure, which can reduce the number of adhesive application steps.

[0063] In some embodiments, the special-shaped double-sided adhesive tape 400 further includes a first protective film 403, a second protective film 402, and a third protective film 404. The first protective film 403 is provided on the side of the second body layer 4012 away from the first body layer 4011; the third protective film 404 is provided on the side of the first body layer 4011 away from the second body layer 4012; the second protective film 402 is located around the second body layer 4012 and between the first body layer 4011 and the first protective film 403. The special-shaped double-sided adhesive tape 400 can be protected by three protective films. When in use, the first protective film 403 and the second protective film 402 are first torn off to bond the second body layer 4012, the first body layer 4011, and the first electromagnetic shielding layer 303, and then the third protective film 404 is torn off to bond the first body layer 4011 to the main body.

[0064] Based on the same inventive concept, corresponding to any of the above embodiments, the embodiment of the present disclosure also provides a flexible circuit board. Figure 3A to Figure 3J As shown, the flexible circuit board includes: a circuit layer 301 and a first covering layer 302 and a first electromagnetic shielding layer 303 sequentially arranged on the circuit layer 301; wherein,

[0065] The first covering layer 302 includes at least one window, and the circuit layer 301 is connected to the first electromagnetic shielding layer 303 at the position of the window; the projection area of ​​the window in the direction perpendicular to the circuit layer 301 (for example, the z-axis direction) is 1 to 30 mm 2 .

[0066] In some embodiments, the shape of the projection is selected from one or more of a rectangle, a circle, and an ellipse.

[0067] In some embodiments, Figure 3B As shown, the shape of the projection is a rectangle, and the aspect ratio of the rectangle is ≥2.

[0068] In some embodiments, a first adhesive layer 309 is further included. The first adhesive layer 309 is disposed on a side of the first electromagnetic shielding layer 303 away from the circuit layer 301 .

[0069] In some embodiments, Figure 3A As shown, the projection of the window in the direction perpendicular to the circuit layer 301 is located between the projections of the first adhesive layer 309 in the direction perpendicular to the circuit layer 301, and the overlap area is 1 to 5 mm2 In such a structure, the first adhesive layer 309 completely or partially covers the window.

[0070] In some embodiments, Figure 3D As shown, the projected area is 5 to 30 mm 2 , the projection of the window in a direction perpendicular to the circuit layer 301 and the projection of the first adhesive layer 309 in a direction perpendicular to the circuit layer 301 do not overlap, and the distance a1 between the two is ≥0.2 mm.

[0071] In some embodiments, a filling structure 310 is disposed in the opening; a thickness H2 of the filling structure 310 is ≤ a height H1 of the opening in a direction perpendicular to the circuit layer 301 .

[0072] In some embodiments, Figure 3E As shown, the material of the filling structure 310 is a conductor material, and the filling structure 310 connects the first electromagnetic shielding layer 303 and the circuit layer 301 .

[0073] In some embodiments, Figure 3F to Figure 3J As shown, the material of the filling structure is an insulating material, and the first electromagnetic screen layer 303 includes a bending structure, which is arranged in the opening and between the filling structure 310 and the circuit layer 301 .

[0074] In some embodiments, Figure 3G As shown, the difference between the first bonding force between the filling structure 310 and the first electromagnetic shielding layer 303 (corresponding to the A1 contact surface), the second bonding force between the filling structure and the first adhesive layer 309 (corresponding to the A2 contact surface), and the third bonding force of the first adhesive layer 309 away from the filling structure 310 (corresponding to the A3 contact surface) is no more than 10%.

[0075] In some embodiments, Figure 3G As shown, the filling structure 310 includes a first surface close to the circuit layer 301, a second surface away from the circuit layer 301, and a side surface between the first surface and perpendicular to the circuit layer 301; in the direction of the first surface, the distance a2 between the side surface and the first electromagnetic shielding layer 303 is greater than zero.

[0076] In some embodiments, the filling structure 310 includes polyimide with single-sided adhesive, polyethylene terephthalate with single-sided adhesive, or double-sided adhesive.

[0077] In some embodiments, the elastic modulus of the double-sided adhesive is ≥100 MPa; in some embodiments, Figure 3H As shown, the double-sided adhesive includes a substrate 313 .

[0078] In some embodiments, Figure 3J As shown, the filling structure 310 and the first adhesive layer 309 are formed by special-shaped double-sided adhesive tape; Figure 4 The special-shaped double-sided adhesive tape includes a first body layer 4011 and a second body layer 4012 located on the first body layer 4011 , and the size of the second body layer 4012 corresponds to that of the filling structure 310 .

[0079] In some embodiments, Fig. 3I As shown, the filling structure 310 includes a first surface close to the circuit layer 301 , a second surface away from the circuit layer 301 , and a side surface between the first surface and inclined relative to the circuit layer 301 .

[0080] In some embodiments, Fig. 3I As shown, the material of the filling structure 310 is a liquid curing material, such as ink or glue; in some embodiments, the elastic modulus of the filling structure 310 is 200 MPa to 3 GPa.

[0081] In some embodiments, the thickness of the first adhesive layer 309 is 0.05-0.20 mm; in some embodiments, the first adhesive layer 309 is a double-sided adhesive containing a substrate; the thickness of the substrate of the double-sided adhesive containing a substrate is less than 1 / 10 of the total thickness; the elastic modulus of the substrate of the double-sided adhesive containing a substrate is less than 2 GPa; in some embodiments, the first adhesive layer 309 is a double-sided adhesive without a substrate, and the elastic modulus of the double-sided adhesive without a substrate is 10 KPa-50 MPa.

[0082] In some embodiments, Figure 3A to Figure 3J As shown, it also includes a second covering layer 304 and a second electromagnetic shielding layer 305; the second covering layer 304 and the second electromagnetic shielding layer 305 are sequentially arranged on the side of the circuit layer 301 away from the first covering layer.

[0083] The flexible circuit board of the above embodiment has the beneficial effects of the above corresponding embodiments, which will not be described in detail here.

[0084] Based on the same inventive concept, the present disclosure also provides a special-shaped double-sided adhesive tape. Figure 4 As shown, the special-shaped double-sided adhesive tape 400 includes a first body layer 4011, a second body layer 4012, a first protective film 403, a second protective film 402 and a third protective film 404; wherein,

[0085] The second body layer is located on the first body layer 4011 and the area of ​​the second body layer 4012 is smaller than that of the first body layer 4011;

[0086] A first protective film 403 is disposed on a side of the second body layer away from the first body layer 4011 ; a third protective film 404 is disposed on a side of the first body layer 4011 away from the second body layer 4012 ;

[0087] The second protection film 402 is located around the second body layer 4012 and between the first body layer 4011 and the first protection film 403 .

[0088] Based on the same inventive concept, the present disclosure also provides an electronic device, comprising the flexible circuit board of any of the aforementioned embodiments.

[0089] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of simplicity.

[0090] The embodiments of the present disclosure are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A flexible circuit board, characterized in that: The flexible circuit board comprises: a circuit layer, and a first covering layer and a first electromagnetic shielding layer sequentially arranged on the circuit layer; wherein, The first covering layer includes at least one opening, and the circuit layer is connected to the first electromagnetic shielding layer at the position of the opening; the projection area of ​​the opening in a direction perpendicular to the circuit layer is 1 to 30 mm 2 .

2. The flexible circuit board according to claim 1, characterized in that: The shape of the projection is selected from one or more of a rectangle, a circle, and an ellipse.

3. The flexible circuit board according to claim 1, characterized in that: The projection is in the shape of a rectangle, and the aspect ratio of the rectangle is ≥2.

4. The flexible circuit board according to claim 1, characterized in that: It also includes a first adhesive layer, which is arranged on a side of the first electromagnetic shielding layer away from the circuit layer.

5. The flexible circuit board according to claim 4, characterized in that: The overlapping area of ​​the projection of the window in a direction perpendicular to the circuit layer and the projection of the first adhesive layer in a direction perpendicular to the circuit layer is 1 to 5 mm 2 .

6. The flexible circuit board according to claim 4, characterized in that: The projection area is 5 to 30 mm 2 , the projection of the window in a direction perpendicular to the circuit layer and the projection of the first adhesive layer in a direction perpendicular to the circuit layer have no overlap and the distance between the two is ≥0.2mm.

7. The flexible circuit board according to claim 4, characterized in that: A filling structure is arranged in the opening; the thickness of the filling structure is less than or equal to the height of the opening in a direction perpendicular to the circuit layer.

8. The flexible circuit board according to claim 7, characterized in that: The filling structure is made of a conductive material, and the filling structure connects the first electromagnetic shielding layer and the circuit layer.

9. The flexible circuit board according to claim 7, characterized in that: The material of the filling structure is an insulating material. The first electromagnetic screen layer includes a bending structure. The bending structure is arranged in the opening and located between the filling structure and the circuit layer.

10. The flexible circuit board according to claim 9, characterized in that: The difference among a first bonding force between the filling structure and the first electromagnetic shielding layer, a second bonding force between the filling structure and the first adhesive layer, and a third bonding force of the first adhesive layer away from the filling structure is no more than 10%.

11. The flexible circuit board according to claim 9, characterized in that: The filling structure includes a first surface close to the circuit layer, a second surface away from the circuit layer, and a side surface between the first surface and perpendicular to the circuit layer; in the direction of the first surface, the distance between the side surface and the first electromagnetic shielding layer is greater than zero.

12. The flexible circuit board according to claim 11, characterized in that: The filling structure includes polyimide with adhesive on one side, polyethylene terephthalate with adhesive on one side, or double-sided adhesive.

13. The flexible circuit board according to claim 12, characterized in that: The elastic modulus of the double-sided adhesive tape is ≥100 MPa; and / or the double-sided adhesive tape comprises a substrate.

14. The flexible circuit board according to claim 11, characterized in that: The filling structure and the first adhesive layer are formed by a special-shaped double-sided adhesive tape; the special-shaped double-sided adhesive tape comprises a first body layer and a second body layer located on the first body layer, and the second body layer and the filling structure have corresponding sizes.

15. The flexible circuit board according to claim 9, characterized in that: The filling structure includes a first surface close to the circuit layer, a second surface away from the circuit layer, and a side surface between the first surface and the second surface and inclined relative to the circuit layer.

16. The flexible circuit board according to claim 15, characterized in that: The material of the filling structure is a liquid solidifying material; and / or The elastic modulus of the filling structure is 200 MPa to 3 GPa.

17. The flexible circuit board according to claim 4, characterized in that: The thickness of the first adhesive layer is 0.05 to 0.20 mm; or The first adhesive layer is a double-sided adhesive containing a substrate; the substrate thickness of the double-sided adhesive containing a substrate is less than 1 / 10 of the total thickness; the elastic modulus of the substrate of the double-sided adhesive containing a substrate is less than 2 GPa; or The first adhesive layer is a double-sided adhesive without a substrate, and the elastic modulus of the double-sided adhesive without a substrate is 10 KPa to 50 MPa.

18. The flexible circuit board according to any one of claims 1 to 17, characterized in that: Also includes a second covering layer and a second electromagnetic shielding layer; The second covering layer and the second electromagnetic shielding layer are sequentially arranged on a side of the circuit layer away from the first covering layer.

19. A special-shaped double-sided adhesive tape, characterized in that: It includes a first body layer, a second body layer, a first protective film, a second protective film and a third protective film; wherein, The second body layer is located on the first body layer and the area of ​​the second body layer is smaller than that of the first body layer; The first protective film is disposed on a side of the second body layer away from the first body layer; the third protective film is disposed on a side of the first body layer away from the second body layer; The second protection film is located around the second body layer and between the first body layer and the first protection film.

20. An electronic device comprising the flexible circuit board according to any one of claims 1 to 18.

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