Flexible circuit board and display device

Abstract

The present disclosure provides a flexible circuit board and a display device. The flexible circuit board includes: a plurality of sub-circuit boards arranged in a stacked manner, the plurality of sub-circuit boards at least including a first sub-circuit board and a second sub-circuit board; and a pressure sensor arranged on the first sub-circuit board, wherein the first sub-circuit board includes: a substrate film; a conductive film arranged on a side of the substrate film away from the second sub-circuit board; an adhesive layer arranged on a side of the conductive film away from the substrate film; a covering layer arranged on a side of the adhesive layer away from the substrate film; and an electromagnetic shielding layer arranged on a side of the covering layer away from the substrate film, wherein at least a portion of the conductive film forms an electrode of the pressure sensor.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a flexible circuit board and a display device. Background Art

[0002] Flexible Printed Circuit (FPC) is a highly reliable and flexible printed circuit board made of flexible film as the substrate. Flexible circuit boards have the characteristics of high wiring density, light weight, thin thickness, good bendability, etc., and are widely used in various display devices such as mobile phones, computers and monitors. Summary of the invention

[0003] In one aspect, a flexible circuit board is provided, comprising: a plurality of stacked sub-circuit boards, the plurality of sub-circuit boards comprising at least a first sub-circuit board and a second sub-circuit board; and a pressure sensor arranged on the first sub-circuit board, wherein the first sub-circuit board comprises: a substrate film; a conductive film arranged on a side of the substrate film away from the second sub-circuit board; an adhesive layer arranged on a side of the conductive film away from the substrate film; a covering layer arranged on a side of the adhesive layer away from the substrate film; and an electromagnetic shielding layer arranged on a side of the covering layer away from the substrate film, wherein at least a portion of the conductive film forms an electrode of the pressure sensor.

[0004] According to some exemplary embodiments, the flexible circuit board includes a main area and a protruding area, the thickness of the main area along a first direction is greater than the thickness of the protruding area along the first direction, the first direction is perpendicular to the surface of the substrate film away from the second sub-circuit board; and the pressure sensor is arranged in the protruding area.

[0005] According to some exemplary embodiments, a portion of the first sub-circuit board is disposed in the main body region, and another portion protrudes relative to the main body region; and the portion of the first sub-circuit board protruding relative to the main body region forms the protruding region.

[0006] According to some exemplary embodiments, a spacing distance between the conductive film and the electromagnetic shielding layer along the first direction is in a range of 34.5 micrometers to 40.5 micrometers.

[0007] According to some exemplary embodiments, a thickness of the adhesive layer along the first direction is about 25 micrometers.

[0008] According to some exemplary embodiments, an orthographic projection of the pressure sensor on the substrate film is spaced apart from an orthographic projection of the main area on the substrate film.

[0009] According to some exemplary embodiments, the protruding region includes a transition region located between the pressure sensor and the main region; and the flexible circuit board includes a plurality of traces disposed in the transition region.

[0010] According to some exemplary embodiments, an orthographic projection of the main area on the substrate film is adjacent to an orthographic projection of the protruding area on the substrate film.

[0011] According to some exemplary embodiments, an area of ​​an orthographic projection of the main region on the substrate film is larger than an area of ​​an orthographic projection of the protruding region on the substrate film.

[0012] According to some exemplary embodiments, the protruding area protrudes from a side surface of the main area, the orthographic projection of the side surface on the substrate forms a dividing line, and the ratio of the size of the orthographic projection of the protruding area on the base film along the direction perpendicular to the dividing line to the size of the orthographic projection of the main area on the base film along the direction perpendicular to the dividing line is in the range of 0.5 to 1.5.

[0013] According to some exemplary embodiments, a ratio of a size of an orthographic projection of the protruding area on the substrate film along a direction parallel to the dividing line to a size of an orthographic projection of the main area on the substrate film along a direction parallel to the dividing line is in a range of 0.15 to 1.

[0014] According to some exemplary embodiments, the size of the orthographic projection of the protruding area on the substrate film along a direction perpendicular to the dividing line is approximately 13.4 mm; and / or, the size of the orthographic projection of the main area on the substrate film along a direction perpendicular to the dividing line is approximately 13.5 mm.

[0015] According to some exemplary embodiments, the main area includes a first sub-circuit board and a second sub-circuit board; or the main area includes a first sub-circuit board, a second sub-circuit board and a third sub-circuit board; or the main area includes a first sub-circuit board, a second sub-circuit board, a third sub-circuit board and a fourth sub-circuit board.

[0016] According to some exemplary embodiments, the main area includes the first sub-circuit board, the second sub-circuit board, the third sub-circuit board, the fourth sub-circuit board and a bonding film, the fourth sub-circuit board includes a substrate film, a conductive film arranged on one side of the substrate film, and an adhesive layer for pasting the substrate film and the conductive film, each of the second sub-circuit board and the third sub-circuit board includes a substrate film, a conductive film arranged on opposite sides of the substrate film, and an adhesive layer for pasting the substrate film and the conductive film, and a bonding film is arranged between the first sub-circuit board and the second sub-circuit board, between the second sub-circuit board and the third sub-circuit board, and between the third sub-circuit board and the fourth sub-circuit board.

[0017] According to some exemplary embodiments, the pressure sensor includes a first electrode and a second electrode, wherein the first electrode and the second electrode are located in a same conductive film.

[0018] According to some exemplary embodiments, materials of the first electrode and the second electrode include copper.

[0019] According to some exemplary embodiments, the material of the base film and the cover layer includes polyimide.

[0020] In another aspect, a display device is provided, comprising the flexible circuit board as described above.

[0021] On the other hand, a display device is provided, comprising: a flexible circuit board as described above; a display panel; and a battery, wherein an orthographic projection of the battery on the display panel is spaced apart from an orthographic projection of the main area on the display panel, and an orthographic projection of the battery on the display panel at least partially overlaps with an orthographic projection of the protruding area on the display panel.

[0022] According to some exemplary embodiments, an orthographic projection of the battery on the display panel at least partially overlaps with an orthographic projection of the pressure sensor on the display panel.

[0023] According to some exemplary embodiments, the display device further includes a spacer member disposed on a side of the display panel facing the pressure sensor, and the electromagnetic shielding layer is in contact with the spacer member. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of a display device according to an embodiment of the present disclosure is shown;

[0026] Figure 2 A partially exploded schematic diagram of a display device provided by an embodiment of the present disclosure;

[0027] Figure 3A and Figure 3B The display device of the embodiment of the present disclosure is respectively Figure 2 A schematic cross-sectional view taken along the I-I' line;

[0028] Figure 4 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure, which shows the connection between the flexible circuit board and the display panel;

[0029] Figure 5 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure;

[0030] FIG. 6A to FIG. 6C They are respectively the flexible circuit board according to the embodiment of the present disclosure Figure 5 A cross-sectional view taken along line II-II';

[0031] Fig. 7A is a perspective view showing an inductive pressure sensor according to some exemplary embodiments of the present disclosure;

[0032] Figure 7B is a perspective view showing a piezoelectric pressure sensor according to some exemplary embodiments of the present disclosure;

[0033] Figure 8 A display device according to some exemplary embodiments of the present disclosure is Figure 1 A local enlarged view of part III;

[0034] Fig. 9 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure;

[0035] Fig. 10A and Fig. 10B The flexible circuit board according to some exemplary embodiments of the present disclosure is Fig. 9 A local enlarged view of part IV;

[0036] Fig.11 According to some exemplary embodiments of the present disclosure, a flexible circuit board is provided along Fig. 9 A schematic cross-sectional view taken along line VV' in FIG.

[0037] Fig.12 yes Figure 1 A schematic plan view of a display device is shown; and

[0038] Fig.13 is a cross-sectional view of a display device according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0040] Unless otherwise defined, the technical terms or scientific terms used in 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 present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" 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.

[0041] In this document, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0042] In this document, unless otherwise specified and limited, the number of layers in the expressions "single-layer board", "double-layer board", "four-layer board", "six-layer board", etc. refers to the number of layers of conductive films in the flexible circuit board. For example, a "single-layer board" is provided with one layer of conductive film, a "double-layer board" is provided with two layers of conductive films, a "four-layer board" is provided with four layers of conductive films, and a "six-layer board" is provided with six layers of conductive films.

[0043] In this document, unless otherwise clearly specified or limited, the term “extending continuously” means that one component extends from another component, or that the two components are formed as a whole.

[0044] It should be noted that, in this document, unless otherwise specifically described or limited, the term “thickness” refers to a dimension along a direction perpendicular to a display surface of a display panel.

[0045] The embodiment of the present disclosure provides a flexible circuit board and a display device. The flexible circuit board includes: a plurality of sub-circuit boards arranged in a stack, the plurality of sub-circuit boards including at least a first sub-circuit board and a second sub-circuit board; and a pressure sensor arranged on the first sub-circuit board, wherein the first sub-circuit board includes: a substrate film; a conductive film arranged on the side of the substrate film away from the second sub-circuit board; an adhesive layer arranged on the side of the conductive film away from the substrate film; a covering layer arranged on the side of the adhesive layer away from the substrate film; and an electromagnetic shielding layer arranged on the side of the covering layer away from the substrate film, wherein at least a portion of the conductive film forms an electrode of the pressure sensor. In the embodiment of the present disclosure, the electrode of the pressure sensor is arranged on the conductive film of the multilayer board, which is conducive to reducing the space occupied by the pressure sensor, thereby facilitating the arrangement of a large-capacity battery.

[0046] It should be understood that a variety of signal routing lines can usually be integrated on a flexible circuit board for transmitting different types of signals. When the number and types of signal routing lines on a flexible circuit board are large, for example, when a variety of signal routing lines for display signals, touch signals, fingerprint recognition signals, etc. are required at the same time, the wiring difficulty in the flexible circuit board will also increase. In this regard, at least a portion of the flexible circuit board can be formed to have a multi-layer routing layer, such as a four-layer or six-layer routing layer, etc., so as to facilitate the arrangement of a variety of routing lines, so that a variety of routing lines can be distributed on different layers, thereby reducing the mutual interference between different types of routing lines. In addition, in the process of making a flexible circuit board with a multi-layer routing layer, it is also necessary to form an insulating layer (and a corresponding adhesive layer) located between adjacent routing layers. If necessary, in order to avoid signal crosstalk between different routing lines, it is also necessary to form an (electromagnetic signal) shielding layer between different routing lines.

[0047] The embodiments of the present disclosure provide a display device, and the type of the display device is not limited, and may be a liquid crystal display device (Liquid Crystal Display, LCD for short) or an electroluminescent display device. In the case where the display device is an electroluminescent display device, the electroluminescent display device may be an organic light-emitting diode (OLED for short) or a quantum dot light-emitting diode (QLED for short).

[0048] Figure 1 FIG. 4 shows a schematic diagram of the display device. Figure 1 As shown, the main structure of the display device includes components such as a frame 1, a cover plate 2, a display panel 3, and a flexible circuit board 4. In the case where the display device is a liquid crystal display device, the display device also includes a backlight assembly. Here, the display panel 3 can be a flexible display panel or a rigid display panel. In the case where the display panel 3 is a flexible display panel, the display device is a flexible display device.

[0049] For example, Figure 1 The upper side of the display panel 3 shown in the figure is the display side, and the lower side is the non-display side; at this time, the flexible circuit board 4 is bent after being bound and placed on the non-display side of the display panel 3, that is, bent to the back of the display panel 3, so as to realize the large-screen design of the display screen.

[0050] For example, the display device provided in the embodiments of the present disclosure may be a product or component having any display function, such as a television, a digital camera, a mobile phone, and a tablet computer.

[0051] like Figure 1 As shown, the longitudinal section of the frame 1 is U-shaped, the display panel 3, the flexible circuit board 4 and other accessories are all arranged in the frame 1, the flexible circuit board 4 is placed below the display panel 3 (i.e., the back side, the side away from the display surface of the display panel 3), and the cover plate 2 is arranged on the side of the display panel 3 away from the flexible circuit board 4. In the case where the display is a liquid crystal display, and the liquid crystal display includes a backlight assembly, the backlight assembly is arranged between the display panel 3 and the flexible circuit board 4.

[0052] like Figure 1 As shown, the display panel 3 may include a display unit 31 and a touch layer 32, and the touch layer 32 may be arranged on the light-emitting side of the display unit 31. For example, when the display panel 3 is an OLED display panel, the touch layer 32 may be arranged on the encapsulation layer of the OLED display panel (it may be directly in contact with the encapsulation layer, or there may be other layers between the encapsulation layer, such as a flat layer, etc.), wherein the encapsulation layer may be an encapsulation substrate or an encapsulation film; when the display panel 3 is a liquid crystal display panel, the touch layer 32 may be embedded in the liquid crystal layer (i.e., In cell); or, the touch layer 32 may be arranged between the color film substrate and the upper polarizer (i.e., On cell). The position of the touch layer 32 is not limited thereto, for example, it may also be arranged inside the display panel 3, and for example, the touch layer 32 is arranged on the side of the cover plate 2 close to the display panel 3.

[0053] Figure 2 This is a partially exploded schematic diagram of a display device provided by an embodiment of the present disclosure. Figure 1 and Figure 2 The display unit 31 may include a display area AA and a non-display area NA located at least on one side of the display area AA. Figure 2 Take the non-display area NA surrounding the display area AA as an example. The display area AA can be defined as an area in which an image is displayed, and the display area AA includes a plurality of sub-pixels for realizing an image. The non-display area NA can be defined as an area in which an image is not displayed, and the non-display area NA is used for wiring. For example, a gate drive circuit can be set in the non-display area NA. In other words, the non-display area can also be called a wiring area or a frame.

[0054] In the case where the display panel 3 includes a touch layer 32, the touch layer 32 can be disposed on the display unit 31. The touch layer 32 can obtain coordinate information from external input (e.g., a user's finger touch), that is, the touch layer 32 can be a touch panel that senses the user's touch; or it can be a fingerprint sensing panel that obtains fingerprint information of the user's finger. For example, the touch layer 32 can sense external input in a capacitive manner. It should be noted that the sensing method of the touch layer 32 in the embodiment of the present disclosure includes but is not limited to the above-mentioned implementation method, and other suitable sensing methods should be within the protection scope of the embodiment of the present disclosure.

[0055] Figure 3A and Figure 3B The display device of the embodiment of the present disclosure is respectively Figure 2 In some embodiments, reference Figure 3A , the touch layer 32 can be formed on the display unit 31 through a continuous process. That is, the touch layer 32 can be directly formed on the display unit 31 after the display unit 31 is formed. Figure 3A For example, when the touch layer 32 is formed in the electroluminescent display device, the touch layer 32 can be directly formed on the encapsulation layer 33. In addition, in order to avoid damaging the encapsulation layer 33 when the touch layer 32 is formed on the encapsulation layer 33, a buffer layer 34 can be formed on the encapsulation layer 33 before the touch layer 32 is formed on the encapsulation layer 33. In other embodiments, refer to Figure 3B , the touch layer 32 may be formed as a separate element, and the touch layer 32 may be adhered to the display unit 31 using the adhesive layer 35. In the case where the touch layer 32 is formed as a separate element (e.g., a separate film layer), the touch layer 32 may further include a carrier film for carrying the touch electrodes. Figure 3B In the illustrated embodiment, the touch layer 32 may include a touch electrode layer 321 and a carrying film 320 carrying the touch electrode layer.

[0056] For example, the carrier film 320 may be a resin film, a glass substrate, a composite film, etc.; the adhesive layer 35 may be a pressure sensitive adhesive (PSA), an optically clear adhesive (OCA), an optically clear resin (OCR), etc.

[0057] It should be noted that in Figure 2 In the illustrated embodiment, the display panel 3 may be rectangular in the shape of the plan view. The "rectangle" here includes not only a substantially rectangular shape, but also a shape similar to a rectangle in consideration of process conditions. On this basis, the display panel 3 has a long side and a short side. In some embodiments, the long side and the short side of the display panel 3 are right angles at each intersecting position (i.e., at the corner). In other embodiments, the corners of the display panel 3 are curved, i.e., the corners are smooth.

[0058] In combination with the above embodiments, refer again to Figure 2 , the touch layer 32 may overlap the display unit 31. In some embodiments, the touch layer 32 may have substantially the same size as the display unit 31, that is, Figure 3A and Figure 3B As shown, the edge of the touch layer 32 can be aligned with the edge of the display unit 31, but the embodiment of the present disclosure is not limited thereto. Optionally, the touch layer 32 can only partially overlap with the display unit 31, for example, the touch layer 32 at least partially overlaps with the display area AA of the display unit 31.

[0059] It should be noted that the touch layer 32 includes a touch area B1 provided with a plurality of touch electrodes and a peripheral area B2 provided at the periphery of the touch area B1 and provided with touch leads electrically connected to the touch electrodes. When the touch layer 32 has substantially the same size as the display unit 31, the touch area B1 corresponds to the display area AA, and the peripheral area B2 corresponds to the non-display area NA.

[0060] On this basis, if Figure 2 As shown, the cover plate 2 may include a light-transmitting area C1 and a light-shielding area C2. The light-transmitting area C1 may at least partially overlap with the display area AA of the display unit 31, and the light-transmitting area C1 may allow light generated from the display unit 31 to pass to the outside so as to be seen by human eyes. The light-shielding area C2 may be arranged at the periphery of the light-transmitting area C1, and may at least partially overlap with the non-display area NA of the display unit 31.

[0061] Figure 4 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure, which shows the connection between the flexible circuit board and the display panel. Figure 51 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure. Figure 2 , Figure 4 and Figure 5 As shown, the flexible circuit board 4 can be bent along the line AL toward the non-display side of the display panel 3, so that the flexible circuit board 4 is located on the back of the display panel 3. The flexible circuit board 4 may include a binding area 41, a main body area 42 and a protruding area 43. The protruding area 43 and the binding area 41 are respectively located on opposite sides of the main body area 42.

[0062] The binding area 41 of the flexible circuit board 4 may include a plurality of binding pins 411. The non-display area NA of the display panel 3 may include a plurality of binding pads. The plurality of binding pins 411 are respectively bound to the plurality of binding pads to achieve binding of the flexible circuit board 4 and the display panel 3.

[0063] For example, in some embodiments, in combination Figure 4 As shown, the non-display area NA of the display panel 3 also includes a driving circuit IC37. The data signals, power signals, etc. sent by the mainboard are electrically connected to the driving circuit IC37 through the wiring on the flexible circuit board 4 (for example, they can be collectively referred to as data signal control lines), processed by the driving circuit IC37, and finally output to the display panel 3, thereby driving the display panel 3 to display.

[0064] The main area 42 of the flexible circuit board 4 may include one or more driving devices, such as a display driving device D1 and / or a touch driving device D2. The main area 42 of the flexible circuit board 4 may also include one or more traces, for example, the traces may include a first trace L1, a second trace L2, and a third trace L3. Exemplarily, the first trace L1 may be a signal trace for transmitting data required for display, the second trace L2 may be a power trace L2, and the third trace L3 may be a touch trace L3. The signal trace L1 may be electrically connected to the display driving device D1, and the touch trace L3 may be electrically connected to the touch driving device D2.

[0065] For example, the driver device may include a driver IC chip. There are many ways (i.e., packaging methods) to combine the driver IC chip with the flexible circuit board 4, such as tape carrier package (TCP), chip on film (COF) packaging, etc. In the TCP method, the flexible circuit board includes a plurality of contact pads, and the plurality of pins of the driver IC chip are welded one-to-one with the plurality of contact pads of the flexible circuit board (e.g., eutectic welding), or are electrically connected one-to-one through anisotropic conductive adhesive (ACF), and at least the welding part is protected by, for example, epoxy resin; in order to increase the bendability of the flexible circuit board under the TCP method, a slit (Slit) may be formed in the packaging part. In the COF packaging method, the flexible circuit board includes a plurality of contact pads, and the plurality of pins of the driver IC chip are directly crimped on the plurality of contact pads of the flexible circuit board through the ACF, so that the plurality of pins of the driver IC chip are electrically connected one-to-one with the plurality of contact pads of the flexible circuit board. For example, the size and arrangement of the contact pads on the flexible circuit board used to combine the driver IC chip can be adjusted accordingly according to different types of packaging methods or driver IC chips to be packaged. For example, these contact pads can be arranged in a long strip or a rectangle. The embodiments of the present disclosure do not limit the packaging method of the driver IC chip.

[0066] It should be noted that the number of the first line L1, the second line L2 and the third line L3 is not limited, and may be one or more. Here, “more than one” may be, for example, at least two.

[0067] Continue to refer to Figure 4 and Figure 5 , one or more traces included in the main area 42 can extend to the extension area 43, and be electrically connected to the mainboard through the binding area or gold fingers included in the extension area 43. For example, the first trace L1 and the second trace L2 can both extend to the extension area 43. In this way, the data signal, power signal, etc. sent by the mainboard can be transmitted to the display panel 3 through the traces on the flexible circuit board 4.

[0068] In an embodiment of the present disclosure, the flexible circuit board 4 may include a pressure sensor 10. The pressure sensor 10 may be configured to obtain touch pressure information about a user's touch operation. For example, the pressure sensor 10 may obtain information indicating whether the user's touch operation involves pressure. In a non-limiting example, the pressure sensor 10 may obtain information about the magnitude of the touch pressure.

[0069] FIG. 6A to FIG. 6C They are respectively the flexible circuit board according to the embodiment of the present disclosure Figure 5 The cross-sectional view taken along the line II-II' in FIG. FIG. 6A to FIG. 6CAs shown, in some embodiments, the body region 42 has a multi-layer board structure.

[0070] For example, Fig. 6A As shown, the main body area 42 may include a first sub-circuit board 51 and a second sub-circuit board 52. Figure 6B As shown, the main body area 42 may include a first sub-circuit board 51 , a second sub-circuit board 52 and a third sub-circuit board 54 .

[0071] For example, Figure 6C As shown, the main body region 42 has a six-layer structure.

[0072] like Figure 6C As shown, the six-layer board structure of the main area 42 can have a combination of "1 layer + 2 layers + 2 layers + 1 layer". The main area 42 can include a first sub-circuit board 51, a second sub-circuit board 52, a third sub-circuit board 54, a fourth sub-circuit board 55 and a laminating film 53. For example, each sub-circuit board can be a copper clad board. The laminating film 53 can include adhesive materials such as PP glue, which is used to bond two adjacent sub-circuit boards. For example, after a plurality of sub-circuit boards are bonded and pressed, they are fixedly connected as a whole functional unit.

[0073] The first sub-circuit board 51 may include: a substrate film 511; a conductive film 512 disposed on one side of the substrate film 511; an adhesive layer 513 disposed on a side of the conductive film 512 away from the substrate film 511; a cover layer 514 disposed on a side of the adhesive layer 513 away from the substrate film 511; and an electromagnetic shielding layer 515 disposed on a side of the cover layer 514 away from the substrate film 511. For example, at least a portion of the conductive film 512 may form an electrode of the pressure sensor 10.

[0074] For example, the substrate film and the covering layer may be made of flexible materials such as polyimide or polyester. The material of the electromagnetic shielding layer is not specifically limited, as long as it has a predetermined stiffness and strength and has heat transfer and electromagnetic shielding functions. For example, the electromagnetic shielding layer may include copper (Cu), nickel (Ni), ferrite, silver (Ag) or their alloys. For another example, the electromagnetic shielding layer may be one or more of conductive rubber, conductive cloth, conductive foam and conductive shielding glue. By providing the electromagnetic shielding layer, the interference of external signals on the signals transmitted by various traces on the flexible circuit board and the pressure sensor can be shielded.

[0075] In this embodiment, the first sub-circuit board 51 has a single-layer board structure, and the pressure sensor 10 is disposed on the single-layer board. With such a design, the thickness of the flexible circuit board at the pressure sensor can be reduced.

[0076] In the embodiments of the present disclosure, reference will be made to Fig. 7A and Figure 7B Several exemplary embodiments of the electrodes of the pressure sensor 10 are described, however, it should be understood that the pressure sensor 10 according to the embodiment of the present disclosure is not limited thereto, and the pressure sensor 10 can be configured as any one of an electrostatic type, an inductive type, a strain gauge type, a piezoelectric type, and a capacitive type according to its operating method.

[0077] For example, Fig. 7A 1 is a perspective view showing an inductive pressure sensor according to some exemplary embodiments of the present disclosure. The pressure sensor 10 may be an inductive pressure sensor. Fig. 7A The inductive pressure sensor 10' may include a plurality of electrodes 101', for example, the electrodes 101' are inductors, such as coils. When the pressure sensor 10' is working, as the pressure applied by the user changes, the current induced in the electrodes 101' will also change accordingly. For example, when a conductor (e.g., a metal housing or a user's finger) approaches the electrodes 101' due to the pressure applied by the user, the current induced in the electrodes 101' may increase. The pressure sensor 10' can sense pressure based on the change in current.

[0078] For example, the pressure sensor 10 may be a strain gauge type pressure sensor. Fig. 7A , the strain gauge type pressure sensor 10' may include an electrode 101'. When the strain gauge type pressure sensor 10' is working, as the pressure applied by the user changes, the length of the electrode 101' will change, and its resistance will also change accordingly. For example, when the pressure applied by the user becomes larger, the resistance of the electrode 101' will increase accordingly. The pressure sensor 10' can sense pressure based on the change in resistance.

[0079] For example, Figure 7B is a perspective view showing a piezoelectric pressure sensor according to some exemplary embodiments of the present disclosure. The pressure sensor 10 may be a piezoelectric pressure sensor. Figure 7B The piezoelectric pressure sensor 10" may include an electrode 101", and the electrode 101" may be formed of a piezoelectric material. When the piezoelectric pressure sensor 10" is working, as the pressure applied by the user changes, the current (i.e., the induced current) converted by the electrode 101" due to the piezoelectric effect will also change accordingly. For example, when the pressure applied by the user increases, the current (i.e., the induced current) converted by the electrode 101" will increase. The pressure sensor 10" can sense pressure based on changes in the induced current.

[0080] In the embodiment of the present disclosure, the electrodes 101 ′, 101 ″ may be disposed in the conductive film 512 , or in other words, at least a portion of the conductive film 512 may constitute the above-mentioned electrodes of the pressure sensor 10 .

[0081] For example, the pressure sensor 10 may be implemented as a self-capacitive type or a mutual-capacitive type, and at least a portion of the conductive film 512 may form an electrode of the pressure sensor 10. In some embodiments of the present disclosure, the conductive film 512 may include copper, that is, it is a copper film layer.

[0082] Return to reference Figure 6C , the second sub-circuit board 52 may include a substrate film 521, a conductive film 522 disposed on opposite sides of the substrate film 521, and an adhesive layer 523 for pasting the substrate film 521 and the conductive film 522. The third sub-circuit board 54 may include a substrate film 541, a conductive film 542 disposed on opposite sides of the substrate film 541, and an adhesive layer 543 for pasting the substrate film 541 and the conductive film 542. The fourth sub-circuit board 55 may include a substrate film 551, a conductive film 552 disposed on one side of the substrate film 551, and an adhesive layer 553 for pasting the substrate film 551 and the conductive film 552. The pasting film 53 is disposed between the first sub-circuit board 51 and the second sub-circuit board 52, between the second sub-circuit board 52 and the third sub-circuit board 54, and between the third sub-circuit board 54 and the fourth sub-circuit board 55.

[0083] For example, the substrate film may be made of flexible materials such as polyimide or polyester.

[0084] Figure 8 A display device according to some exemplary embodiments of the present disclosure is Figure 1 A local enlarged view of part III of FIG. Figure 1 , Figure 6C and Figure 8 At least a portion of the flexible circuit board 4 can be bent to the back of the display panel, so that the pressure sensor 10 is located on the back of the display panel 3.

[0085] like Figure 8 As shown, a gasket member 20 is provided on the back side of the display panel 3. The gasket member 20 is provided between the back side of the display panel 3 and the flexible circuit board 4. The gasket member 20 can reduce or eliminate the damage caused to the display panel 3 by the external impact. The gasket member 20 can absorb or disperse at least part of the external impact, and thus can protect the display panel 3. The material of the gasket member 20 is not specifically limited, as long as it is suitable for absorbing and / or dispersing the impact. For example, the gasket member 20 may include a polymer material such as a polyurethane resin, a carbonate resin, a propylene resin or an ethylene resin, a rubber material or a foamed product thereof. For example, the gasket member 20 may include foam.

[0086] Combined with reference Figure 6C and Figure 8When the flexible circuit board 4 is bent to the back of the display panel 3, the first circuit sub-board 51 can contact the pad member 20. For example, the electromagnetic shielding layer 515 can contact the surface of the pad member 20 away from the display panel 3 (i.e. Figure 8 the lower surface in the middle).

[0087] In the embodiment of the present disclosure, the distance between the conductive film 512 and the electromagnetic shielding layer 515, that is, the distance between the conductive film 512 and the electromagnetic shielding layer 515 in the direction perpendicular to the display panel 3, needs to meet a specified distance range. The specified distance range may be 34.5 microns to 40.5 microns. In this way, the pressure sensor 10 can work normally.

[0088] An adhesive layer 513 and a covering layer 514 are provided between the conductive film 512 and the electromagnetic shielding layer 515. In the embodiment of the present disclosure, the thickness of the adhesive layer 513 can be designed so that the distance between the conductive film 512 and the electromagnetic shielding layer 515 meets the above-mentioned specified distance range. The thickness of the adhesive layer 513 can be designed to be 20 microns to 30 microns, for example, about 25 microns, so that the distance between the conductive film 512 and the electromagnetic shielding layer 515 is within 34.5 microns to 40.5 microns.

[0089] Fig. 9 is a schematic plan view of a flexible circuit board according to some exemplary embodiments of the present disclosure. Fig. 10A and Fig. 10B The flexible circuit board according to some exemplary embodiments of the present disclosure is Fig. 9 A local enlarged view of part IV. Fig.11 According to some exemplary embodiments of the present disclosure, a flexible circuit board is provided along Fig. 9 Schematic cross-sectional view taken along line VV' in FIG.

[0090] Below, we will mainly combine Figures 9 to 11 When describing the particularities of some embodiments of the present disclosure, it should be understood that these embodiments may utilize all the structures in the above-mentioned various embodiments without conflict.

[0091] like Figures 9 to 11 As shown, the flexible circuit board 4 may include a binding area 41, a main body area 42, a protruding area 45 and a protruding area 43. The protruding area 45 and the protruding area 43 are located on the same side of the main body area 42, and each of the protruding area 45 and the protruding area 43 and the binding area 41 are located on opposite sides of the main body area 42.

[0092] Reference Fig.11, the thickness of the main body area 42 of the flexible circuit board 4 is thicker than that of the protruding area 45. For example, the main body area 42 may have a six-layer board structure, and the protruding area 45 may have a single-layer board structure. That is, in the embodiment of the present disclosure, the number of layers of the main body area 42 is greater than the number of layers of the protruding area 45, so that the protruding area 45 is formed as a thinned area relative to the main body area 42.

[0093] As described above, the six-layer board structure of the main body area 42 may have a combination of "1 layer + 2 layers + 2 layers + 1 layer". The main body area 42 may include a first sub-circuit board 51, a second sub-circuit board 52, a third sub-circuit board 54, a fourth sub-circuit board 55 and a laminating film 53. The protruding area 45 may be led out from the first sub-circuit board 51. That is, the first sub-circuit board 51 may protrude from the main body area 42, and the protruding portion of the first sub-circuit board 51 forms the protruding area 45.

[0094] In an embodiment of the present disclosure, the pressure sensor 10 may be disposed in the protruding area 45 .

[0095] For example, the pressure sensor 10 may include a first electrode 101 and a second electrode 102 , and the first electrode 101 and the second electrode 102 may be located in the same conductive film, that is, both located in the conductive film 512 .

[0096] For example, the first electrode 101 and the second electrode 102 of the pressure sensor 10 may be the electrode 101' or the electrode 101". In some embodiments, the first electrode 101 and the second electrode 102 may sense pressure based on a change in resistance. For example, as the pressure applied by the user changes, the length of the electrode 101' changes, and its resistance changes accordingly. The pressure sensor 10 is capable of sensing pressure based on a change in resistance. In some embodiments, the first electrode 101 and the second electrode 102 may sense pressure based on a change in capacitance. For example, as the pressure applied by the user changes, the capacitance between the first electrode 101 and the second electrode 102 and the touch body changes. The pressure sensor 10 is capable of sensing pressure based on a change in capacitance. The working principle and method of the pressure sensor 10 may refer to the above description of Fig. 7A and Figure 7B Description.

[0097] It should be noted that the pressure sensor 10 in the embodiment of the present disclosure is not limited to the above-mentioned manner, and various types of pressure sensors known in the relevant field may be used.

[0098] In an embodiment of the present disclosure, the pressure sensor 10 is integrated into a display device such as a mobile phone, a computer, etc., and can be used to sense the pressure of a touch subject (such as a user's finger) pressing the display screen, thereby being able to control the display device to perform different operations based on different pressures.

[0099] The orthographic projection of each of the main area 42 and the protruding area 45 on the display panel or the substrate film has a rectangular shape. The "rectangle" here includes not only a basic rectangular shape, but also a shape similar to a rectangle in consideration of process conditions. On this basis, the main area 42 has a long side and a short side. In some embodiments, the long side and the short side of the main area 42 are right angles at each intersecting position (i.e., the corner). In other embodiments, the corners of the main area 42 are curved, i.e., the corners are smooth.

[0100] like Fig. 9 As shown, the direction in which the short side of the main body region 42 extends is defined as a first direction A1, and the direction in which the long side extends is defined as a second direction A2.

[0101] like Fig.11 As shown, the protruding area 45 may include: a substrate film 511; a conductive film 512 disposed on one side of the substrate film 511; an adhesive layer 513 disposed on the side of the conductive film 512 away from the substrate film 511; a cover layer 514 disposed on the side of the adhesive layer 513 away from the substrate film 511; and an electromagnetic shielding layer 515 disposed on the side of the cover layer 514 away from the substrate film 511. For example, at least a portion of the conductive film 512 may form an electrode of the pressure sensor 10. The structure of the pressure sensor 10 may refer to the description of the various embodiments above, and will not be repeated here.

[0102] In the embodiment of the present disclosure, the pressure sensor 10 is disposed on the protruding portion 45 of the flexible circuit board 4 , that is, disposed in the protruding thinned area.

[0103] The orthographic projection of the main area 42 on the substrate film 511 is adjacent to the orthographic projection of the protruding area 45 on the substrate film 511 , and the area of ​​the orthographic projection of the main area 42 on the substrate film 511 is larger than the area of ​​the orthographic projection of the protruding area 45 on the substrate film 511 .

[0104] The protruding area 45 protrudes from the side surface 425 of the main body area 42 , and the orthographic projection of the side surface 425 on the base film 511 forms a boundary line JL.

[0105] The orthographic projection of the protruding area 45 on the substrate film 511 is perpendicular to the direction of the boundary line JL (i.e. Fig. 9The ratio of the dimension H1 of the protruding area 45 (in the A1 direction) to the dimension H2 of the orthographic projection of the main area 42 on the substrate film 511 along the direction perpendicular to the dividing line is in the range of 0.5-1.5. For example, the dimension H1 of the orthographic projection of the protruding area 45 on the substrate film 511 along the direction perpendicular to the dividing line is about 13.4 mm; and / or the dimension H2 of the orthographic projection of the main area 42 on the substrate film 511 along the direction perpendicular to the dividing line is about 13.5 mm.

[0106] For example, the orthographic projection of the protruding area 45 on the substrate film 511 is parallel to the direction of the dividing line (i.e. Fig. 9 The ratio of the dimension W1 of the main area 42 along the A2 direction in the direction parallel to the dividing line to the dimension W2 of the orthographic projection of the main area 42 on the substrate film 511 is in the range of 0.15 to 1.

[0107] For example, the orthographic projection of the area where the pressure sensor 10 is located on the base film 511 is substantially rectangular in shape, and the dimension W3 of the rectangle along the direction A2 is approximately 15 mm, and the dimension H3 along the direction A1 is approximately 10 mm.

[0108] The orthographic projection of the main body area 42 on the substrate film 511 is substantially rectangular in shape. The size of the rectangle along the direction A2 is about 58 mm, and the size along the direction A1 is about 13.5 mm.

[0109] Fig.12 yes Figure 1 A partial plan view of a display device is shown. Fig.13 is a cross-sectional view of a display device according to some exemplary embodiments of the present disclosure. Figures 1 to 13 The display device may further include a battery 6. The battery 6 may supply power to various components of the display device.

[0110] It should be noted that the expression "battery" herein may include any form of power storage component, including but not limited to, lithium batteries, battery compartments with protective shells, etc. For example, the battery 6 may include: a battery bag containing battery cells, a protection circuit module (PCM) (e.g., a circuit board) electrically connected to the terminals pulled out of the battery bag, and a shell (e.g., a PCM shell or a PCM shell) for protecting the PCM. According to various embodiments, the shell containing the PCM can be fixed to the battery bag as an assembly structure for improving impact resistance, thereby preventing the components of the rechargeable battery (e.g., the battery bag, PCM, or terminals) from being damaged even when an external impact is applied to the electronic device.

[0111] The orthographic projection of the battery 6 on the display panel 3 does not overlap with the orthographic projection of the main body area 42 on the display panel 3. The main body area 42 has a thicker six-layer plate structure, and the battery 6 does not extend below the main body area 42.

[0112] The orthographic projection of the battery 6 on the display panel 3 at least partially overlaps with the orthographic projection of the protruding area 45 on the display panel 3. For example, the orthographic projection of the battery 6 on the display panel 3 at least partially overlaps with the orthographic projection of the protruding area 45 on the display panel 3.

[0113] The orthographic projection of the battery 6 on the display panel 3 at least partially overlaps with the orthographic projection of the pressure sensor 10 on the display panel 3. For example, the orthographic projection of the battery 6 on the display panel 3 covers the orthographic projection of the pressure sensor 10 on the display panel 3.

[0114] In the embodiment of the present disclosure, the protruding area 45 is designed to be thinner than the main area 42, so that the battery 6 can extend below the protruding area 45. In this way, the area of ​​the battery 6 equipped in the display device is increased, and accordingly, the capacity of the battery 6 can be increased.

[0115] The pressure sensor 10 is spaced apart from the main body area 42, that is, the orthographic projection of the pressure sensor 10 on the display panel 3 is spaced apart from the orthographic projection of the main body area 42 on the display panel 3. In this way, the protruding area 45 also includes a transition area 452. Fig. 9 As shown, transition region 452 is located between pressure sensor 10 and body region 42 .

[0116] For example, the orthographic projection of the transition zone 452 on the substrate film 511 is substantially rectangular in shape, and the size of the rectangle along the direction A2 is about 15 mm, and the size along the direction A1 is about 3 mm.

[0117] In the embodiment of the present disclosure, the transition region 452 can be used as a wiring region. Fig. 9 As shown, at least some of the routing lines (such as the first routing line L1, the second routing line L2 and the third routing line L3) can be arranged in the transition area 452. In this way, the area of ​​the main area 42 can be further reduced, for example, the width of the main area 42 can be reduced ( Fig. 9 In this way, the capacity of the battery 6 can be further increased.

[0118] In an embodiment of the present disclosure, a pressure sensor is arranged on a single-layer board protruding from the main area of ​​the six-layer board. Through such a design, the battery can be avoided. When the display device is a small-sized display device such as a mobile phone, such an avoidance design is particularly advantageous and can increase the capacity of the battery.

[0119] In the specific implementation process, the flexible circuit board 4 can be bent to the back of the display panel to realize the narrow frame design of the display device. The display device provided in the embodiment of the present disclosure can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, etc. Other essential components of the display device should be understood by ordinary technicians in the field, and will not be repeated here, nor should they be used as a limitation to the embodiment of the present disclosure.

[0120] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A flexible circuit board, characterized in that: The flexible circuit board comprises: A plurality of sub-circuit boards are stacked, the plurality of sub-circuit boards comprising at least a first sub-circuit board and a second sub-circuit board; and a pressure sensor disposed on the first sub-circuit board, Wherein, the first sub-circuit board comprises: Base film; A conductive film disposed on a side of the substrate film away from the second sub-circuit board; An adhesive layer disposed on a side of the conductive film away from the substrate film; A covering layer disposed on a side of the adhesive layer away from the substrate film; and An electromagnetic shielding layer is arranged on a side of the cover layer away from the substrate film, Wherein, at least a portion of the conductive film forms an electrode of the pressure sensor.

2. The flexible circuit board according to claim 1, wherein: The flexible circuit board comprises a main body area and a protruding area, the thickness of the main body area along a first direction is greater than the thickness of the protruding area along the first direction, and the first direction is perpendicular to the surface of the substrate film away from the second sub-circuit board; and The pressure sensor is disposed in the protruding area.

3. The flexible circuit board according to claim 2, wherein: A portion of the first sub-circuit board is disposed in the main body area, and another portion thereof protrudes relative to the main body area; and The portion of the first sub-circuit board that protrudes relative to the main area forms the protruding area.

4. The flexible circuit board according to any one of claims 1 to 3, wherein: The spacing distance between the conductive film and the electromagnetic shielding layer along the first direction is in the range of 34.5 micrometers to 40.5 micrometers.

5. The flexible circuit board according to claim 4, wherein: The thickness of the bonding layer along the first direction is 25 micrometers.

6. The flexible circuit board according to claim 2, wherein: The orthographic projection of the pressure sensor on the substrate film is spaced apart from the orthographic projection of the main body area on the substrate film.

7. The flexible circuit board according to claim 6, wherein: The protruding region includes a transition region located between the pressure sensor and the main body region; and The flexible circuit board includes a plurality of traces disposed in the transition region.

8. The flexible circuit board according to claim 2, wherein: The orthographic projection of the main area on the substrate film is adjacent to the orthographic projection of the protruding area on the substrate film.

9. The flexible circuit board according to claim 8, wherein: The area of ​​the orthographic projection of the main body region on the substrate film is larger than the area of ​​the orthographic projection of the protruding region on the substrate film.

10. The flexible circuit board according to claim 9, wherein: The protruding area protrudes from a side surface of the main area, and the orthographic projection of the side surface on the substrate film forms a dividing line. The ratio of the size of the orthographic projection of the protruding area on the substrate film along the direction perpendicular to the dividing line to the size of the orthographic projection of the main area on the substrate film along the direction perpendicular to the dividing line is in the range of 0.5 to 1.

5.

11. The flexible circuit board according to claim 10, wherein: The ratio of the size of the orthographic projection of the protruding area on the substrate film along the direction parallel to the dividing line to the size of the orthographic projection of the main area on the substrate film along the direction parallel to the dividing line is in the range of 0.15 to 1.

12. The flexible circuit board according to claim 10, wherein: The dimension of the orthographic projection of the protruding area on the substrate film along the direction perpendicular to the dividing line is 13.4 mm; and / or the dimension of the orthographic projection of the main area on the substrate film along the direction perpendicular to the dividing line is 13.5 mm.

13. The flexible circuit board according to claim 2 or 3, wherein: The main body area includes a first sub-circuit board and a second sub-circuit board; or the main body area includes a first sub-circuit board, a second sub-circuit board and a third sub-circuit board; or the main body area includes a first sub-circuit board, a second sub-circuit board, a third sub-circuit board and a fourth sub-circuit board.

14. The flexible circuit board according to claim 13, wherein: The main area includes the first sub-circuit board, the second sub-circuit board, the third sub-circuit board, the fourth sub-circuit board and a bonding film. The fourth sub-circuit board includes a substrate film, a conductive film arranged on one side of the substrate film, and an adhesive layer for pasting the substrate film and the conductive film. Each of the second sub-circuit board and the third sub-circuit board includes a substrate film, a conductive film arranged on opposite sides of the substrate film, and an adhesive layer for pasting the substrate film and the conductive film. A bonding film is arranged between the first sub-circuit board and the second sub-circuit board, between the second sub-circuit board and the third sub-circuit board, and between the third sub-circuit board and the fourth sub-circuit board.

15. The flexible circuit board according to claim 2, wherein: The pressure sensor includes a first electrode and a second electrode, wherein the first electrode and the second electrode are located in the same conductive film.

16. The flexible circuit board according to claim 15, wherein: The material of the first electrode and the second electrode includes copper.

17. The flexible circuit board according to claim 1, wherein: The materials of the base film and the cover layer include polyimide.

18. A display device comprising the flexible circuit board according to any one of claims 1 to 17.

19. A display device comprising: The flexible circuit board according to claim 2; Display panel; and Battery, The orthographic projection of the battery on the display panel is spaced apart from the orthographic projection of the main area on the display panel, and the orthographic projection of the battery on the display panel at least partially overlaps with the orthographic projection of the protruding area on the display panel.

20. The display device according to claim 19, wherein: An orthographic projection of the battery on the display panel at least partially overlaps with an orthographic projection of the pressure sensor on the display panel.

21. The display device according to claim 19, wherein: The display device further includes a spacer member disposed on a side of the display panel facing the pressure sensor, and the electromagnetic shielding layer is in contact with the spacer member.

Images