CN117222102A

CN117222102A - Flexible circuit board and electronic equipment

Info

Publication number: CN117222102A
Application number: CN202311469670.3A
Authority: CN
Inventors: 胡湘; 韩晔; 王晓岩; 杨帆; 罗浩
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2023-11-07
Filing date: 2023-11-07
Publication date: 2023-12-12
Anticipated expiration: 2043-11-07
Also published as: CN117222102B

Abstract

The application discloses a flexible circuit board and electronic equipment, and belongs to the technical field of electronic equipment. The flexible circuit board includes: the fixed area and the non-fixed area are distributed along the length direction of the flexible circuit board, at least one of two opposite ends of the non-fixed area is connected with the fixed area, and the non-fixed area can be bent and deformed; the non-fixed region comprises a first sub-region and a second sub-region, the first sub-region and the second sub-region are distributed along the length direction of the flexible circuit board, the first sub-region is connected with the second sub-region, and the rigidity of the first sub-region is larger than that of the second sub-region. The electronic equipment comprises a shell, a rotating shaft mechanism and the flexible circuit board, wherein the shell is rotationally connected with the rotating shaft mechanism. The application is beneficial to reducing the occurrence of instability of the flexible circuit board, enhancing the reliability of the flexible circuit board and solving the problem that the display screen is not easy to have stamping and abnormal sound.

Description

Flexible circuit board and electronic equipment

Technical Field

The present application relates to the field of electronic devices, and in particular, to a flexible circuit board and an electronic device.

Background

With the development of technology, various electronic devices such as mobile phones, tablet computers, notebook computers and smart phones are emerging; in order to realize the convenience of the electronic device and the requirement of a large screen, foldable electronic devices are emerging.

For a foldable electronic device, for example, a mobile phone includes a main frame, a rotating shaft mechanism and an auxiliary frame, the main frame and the auxiliary frame are rotatably connected through the rotating shaft mechanism, and a main board on the main frame of the mobile phone is electrically connected with a main board on the auxiliary board through a flexible circuit board passing through the rotating shaft mechanism. The flexible circuit board is fixed with the reinforcing structure on the main frame, the reinforcing structure on the auxiliary frame and the base of the rotating shaft mechanism, and thus the part of the flexible circuit board between the fixed position of the reinforcing structure on the main frame and the fixed position of the base of the rotating shaft mechanism and the part of the flexible circuit board between the fixed position of the reinforcing structure on the auxiliary frame and the fixed position of the base of the rotating shaft mechanism can be called as a shaft penetrating section of the flexible circuit board. However, as the foldable electronic device is lighter and thinner, the space left for the shaft penetrating section in the thickness direction of the foldable electronic device is smaller and smaller, so that the shaft penetrating section is easy to be unstable in the folding and unfolding processes of the rotating shaft mechanism, the reliability of the shaft penetrating section is affected, and the problems of stamping, abnormal sound and the like of the display screen are caused.

Disclosure of Invention

The application provides a flexible circuit board and electronic equipment, which are used for solving the technical problem that a shaft penetrating section of the flexible circuit board is easy to be unstable in the folding and unfolding processes of a rotating shaft mechanism.

The technical scheme is as follows:

a first aspect of the present application provides a flexible circuit board, comprising: a fixed region and a non-fixed region;

the non-fixed areas and the fixed areas are distributed along the length direction of the flexible circuit board, at least one of the two opposite ends of the non-fixed areas is connected with the fixed areas, and the non-fixed areas can be bent and deformed;

the non-fixed region comprises a first sub-region and a second sub-region, the first sub-region and the second sub-region are distributed along the length direction of the flexible circuit board, the first sub-region is connected with the second sub-region, and the rigidity of the first sub-region is larger than that of the second sub-region.

Through adopting above-mentioned scheme, after applying flexible circuit board to electronic equipment such as collapsible electronic equipment, fixed district and collapsible electronic equipment's corresponding part are fixed, the second subregion of non-fixed district is crooked form, the first subregion of non-fixed district presents nearly sharp form, in collapsible electronic equipment's expansion and folding process, because the rigidity in the first subregion of non-fixed district is greater than the rigidity in second subregion, be favorable to restraining the production of second subregion bistable state through first subregion like this, thereby be favorable to reducing flexible circuit board unstability's phenomenon and take place, flexible circuit board's reliability has been strengthened, the problem of moulding print, abnormal response also is difficult for appearing in the display screen.

In some implementations, the number of second subregions is a plurality and the number of first subregions is a plurality;

the plurality of second sub-areas and the plurality of first sub-areas in the non-fixed area are alternately arranged in the length direction of the flexible circuit board, wherein the second sub-areas are positioned between two adjacent first sub-areas.

By adopting the scheme, according to the application scenes of different electronic equipment, the first subareas and the second subareas are arranged, and the bistable state of the second subareas can be better restrained by arranging the second subareas between two adjacent first subareas, so that the occurrence of the phenomenon of instability of the flexible circuit board is reduced.

In some implementations, the non-fixed region is flanked by first sub-regions.

By adopting the scheme, as the fixed area is connected with the non-fixed area and the fixed area is fixed with the corresponding part of the foldable electronic equipment, the first subarea is connected with the fixed area, which is beneficial to reducing the occurrence of the instability phenomenon of the whole non-fixed area.

In some implementations, the flexible circuit board includes a conductive structural layer and a stiffening layer that are stacked in a thickness direction of the flexible circuit board;

the reinforcing layer is arranged in the fixed area, and the conductive structure layer covers the fixed area and the non-fixed area.

By adopting the scheme, the mechanical strength and stability of the flexible circuit board are enhanced by utilizing the reinforcing layer, and the reliability and the service life of the flexible circuit board are improved; the conductive structure layer can realize the transmission of electric signals and is used as the conduction and grounding of a power supply. In addition, the reinforcing layer is arranged in the fixed area, which is beneficial to the fixed connection between the fixed area and the foldable electronic equipment.

In some implementations, the flexible circuit board further includes a first additional layer, the first additional layer being located in the first sub-region;

at least one of the opposite sides of the conductive structure layer is provided with a first additional layer.

By adopting the scheme, the first subarea is more than the second subarea by using the mode of adding the first additional layers, so that the rigidity of the first subarea is larger than that of the second subarea, and the phenomenon of instability of the flexible circuit board is reduced.

In some implementations, the material of the first additional layer is foam, polyester resin, fiberglass cloth, or polyimide.

By adopting the scheme, different types of materials can be selected according to the application scene which is not needed, so that the requirement that the rigidity of the first subarea is larger than that of the second subarea is met.

In some implementations, the conductive structure layer includes a conductive layer having opposing first and second sides;

the reinforcing layer is positioned on one side of the first side surface of the conductive layer, or/and the reinforcing layer is positioned on one side of the second side surface of the conductive layer.

Through adopting above-mentioned scheme, utilize the conducting layer can realize the transmission of signal of telecommunication to and as switching on and the earthing use of power, and set up the stiffening layer at the conducting layer relative first side and the second side in at least one side, can fix the stiffening layer with the part that corresponds in the electronic equipment like this, the conducting layer is fixed with the part that corresponds in the electronic equipment like this indirectly, reduces the possibility of damaging the flexible circuit board when being convenient for subassembly and maintenance.

In some implementations, the conductive layer has at least one first recessed groove thereon, the first recessed groove being located in the second sub-region.

By adopting the scheme, the first concave groove is formed in the conductive layer positioned in the second sub-region, and the conductive layer positioned in the first sub-region is not grooved, or the groove depth of the conductive layer positioned in the first sub-region is smaller than that of the first concave groove, so that the rigidity of the first sub-region is larger than that of the second sub-region, and the phenomenon of instability of the flexible circuit board is reduced.

In some implementations, the first recess groove is stepped in a thickness direction of the flexible circuit board.

Through adopting above-mentioned scheme, first indent is echelonment for the rigidity in the different positions of second subregion is the gradual change, in order to satisfy the demand of different application scenario, thereby reduces the phenomenon emergence of flexible circuit board unstability.

In some implementations, the conductive layer includes at least one first wire; the part of the first lead, which is positioned in the first subarea, is a first sub-line, the part of the first lead, which is positioned in the second subarea, is a second sub-line, and the first sub-line is electrically connected with the second sub-line;

the orthographic projection area of the second sub-line in the first plane is smaller than that of the first sub-line in the first plane, and the first plane is parallel to the length direction and the width direction of the flexible circuit board respectively.

By adopting the scheme, different first leads are utilized to realize different functions, such as electric signal transmission, and conduction and grounding as a power supply. Meanwhile, in the plurality of first wires, the first sub-wires and the second sub-wires of at least one first wire are designed, so that the rigidity of the first sub-area is higher than that of the second sub-area after the orthographic projection area of the second sub-wires on the same first wire is smaller than that of the first sub-wires.

In some implementations, the width of the first sub-line is greater than the width of at least a portion of the structure of the second sub-line in a width direction of the flexible circuit board; or/and, the second sub-line is provided with at least one first hole, and the first sub-line is of a solid structure.

By adopting the scheme, different modes can be adopted according to different requirements, and the first sub-line and the second sub-line of at least one first wire are designed.

In some implementations, the conductive structure layer further includes a base material layer, and the base material layer and the conductive layer are stacked in a thickness direction of the flexible circuit board.

By adopting the above scheme, the substrate layer is used as a main supporting part of the flexible circuit board, and has insulating property.

In some implementations, the substrate layer has at least one second recessed groove thereon, the second recessed groove being located in the second sub-region.

By adopting the scheme, the substrate layer positioned in the second subarea is provided with the second concave groove, so that the rigidity of the first subarea is higher than that of the second subarea, and the processing and manufacturing of the flexible circuit board are facilitated.

In some implementations, the conductive structure layer further includes a cover layer; in the thickness direction of the flexible circuit board, the cover layer, the conductive layer and the base material layer are laminated in this order.

By adopting the scheme, the conductive layer is protected by the covering layer, so that the conductive layer is prevented from being corroded and damaged by the external environment.

In some implementations, the cover layer has at least one third recessed channel thereon, the third recessed channel being located in the second sub-region.

By adopting the scheme, the cover layer positioned in the second subarea is provided with the third concave groove, so that the rigidity of the first subarea is higher than that of the second subarea, and the processing and manufacturing of the flexible circuit board are facilitated.

In some implementations, the number of conductive structure layers is a plurality, and the plurality of conductive structures are stacked in a thickness direction of the flexible circuit board.

By adopting the scheme, when the number of the conductive structure layers is multiple, the flexible circuit board with high density and high signal-to-noise ratio is formed, and the flexible circuit board has good anti-interference performance and anti-electromagnetic wave interference capability.

In some implementations, the flexible circuit board further includes a second additional layer disposed between adjacent two of the conductive structure layers, and the second additional layer is located in the first sub-region.

By adopting the above scheme, the second additional layer is positioned in the first subarea, and the second subarea is not provided with the second additional layer, and the second subarea can be in the form of a gap, so that the rigidity of the first subarea is higher than that of the second subarea.

In some implementations, the material of the second additional layer is foam, polyester resin, fiberglass cloth, or polyimide.

In some implementations, the flexible circuit board further includes a third additional layer, the third additional layer is further disposed between two adjacent conductive structure layers, and the third additional layer is located in the second sub-region;

the orthographic projection area of the third additional layer in the second plane is smaller than that of the second sub-region in the second plane, and the second plane is parallel to the length direction and the width direction of the flexible circuit board respectively.

By adopting the above-described solution, the second sub-zone is not fully covered with the third additional layer, so that a stiffness of the first sub-zone is achieved which is greater than the stiffness of the second sub-zone.

In some implementations, the third additional layer is provided with at least one second hole.

By adopting the scheme, the scheme that the third additional layer does not fully cover the second subarea is realized by arranging the second holes on the third additional layer, so that the situation that the stress of the non-fixed area is too concentrated can be avoided, and the rigidity of the first subarea is higher than that of the second subarea.

In some implementations, the third additional layer is made of foam, polyester resin, fiberglass cloth, or polyimide.

In some implementations, the cross-section of the first sub-region has an area that is greater than the cross-section of the second sub-region, the cross-section of the first sub-region being parallel to the thickness direction and the width direction of the flexible circuit board, respectively, and the cross-section of the second sub-region being parallel to the thickness direction and the width direction of the flexible circuit board, respectively.

By adopting the scheme, the rigidity of the first sub-zone is more convenient to realize than that of the second sub-zone by making the area of the cross section of the first sub-zone larger than that of the cross section of the second sub-zone.

In some implementations, the flexible circuit board further includes a connection region, the number of connection regions is two, the number of non-fixed regions is two, and the number of fixed regions is three;

the flexible circuit board is provided with a head end and a tail end which are opposite, and the two connecting areas are respectively positioned at the head end and the tail end;

and two ends of a third fixed area are respectively connected with two non-fixed areas, and the third fixed area is positioned between the first fixed area and the second fixed area.

By adopting the scheme, the electric connection between the main board and the auxiliary board in the foldable electronic equipment is realized.

The second aspect of the application provides an electronic device, which comprises a shell, a rotating shaft mechanism and any one of the flexible circuit boards, wherein the shell is rotationally connected with the rotating shaft mechanism;

the rotating shaft mechanism comprises a base, and fixing areas at two ends of the flexible circuit board in the length direction are fixedly connected with the base and the shell respectively.

By adopting the scheme, after the flexible circuit board is applied to the foldable electronic equipment, the fixed area and the corresponding part of the foldable electronic equipment are fixed, the second subarea of the non-fixed area is in a bent shape, the first subarea of the non-fixed area is in a nearly straight line shape, and in the unfolding and folding process of the foldable electronic equipment, the rigidity of the first subarea of the non-fixed area is larger than that of the second subarea, so that the first subarea is favorable for inhibiting the bistable state of the second subarea, thereby being favorable for reducing the occurrence of instability phenomenon of the flexible circuit board, enhancing the reliability of the flexible circuit board, and solving the problems of stamping and abnormal sound of a display screen.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device in a folded state according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of an electronic device in a semi-unfolded state according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of an electronic device in an unfolded state according to an embodiment of the present application;

FIG. 4 is an exploded view of the electronic device of FIG. 3;

FIG. 5 is a schematic diagram of a state of a flexible circuit board before destabilization in a foldable electronic device according to the related art;

FIG. 6 is a schematic diagram of a state of the flexible circuit board after destabilization in a foldable electronic device according to the related art;

FIG. 7 is a simplified schematic diagram of a flexible circuit board in a foldable electronic device in accordance with an embodiment of the application;

FIG. 8 is a schematic diagram of a partial structure of a flexible circuit board in a foldable electronic device in an embodiment of the application;

FIG. 9 is a schematic view showing a partial structure of a flexible circuit board of a first form in an embodiment of the present application;

FIG. 10 is a schematic view of a part of a flexible circuit board in a second form of embodiment of the application;

FIG. 11 is a schematic view showing a partial structure of a flexible circuit board according to a third form of the embodiment of the present application;

FIG. 12 is a schematic flow chart of a method for manufacturing a flexible circuit board with multiple conductive structure layers according to an embodiment of the application;

FIG. 13 is a schematic view of another process for manufacturing a flexible circuit board having multiple conductive structure layers according to an embodiment of the present application;

FIG. 14 is a schematic view of a first form of the windowing scheme for an adhesive layer in accordance with an embodiment of the present application;

FIG. 15 is a schematic view of a second form of windowing for an adhesive layer in accordance with an embodiment of the present application;

FIG. 16 is a schematic view of a third form of windowing for an adhesive layer in accordance with an embodiment of the present application;

FIG. 17 is a schematic view of a fourth form of windowing for an adhesive layer in accordance with an embodiment of the present application;

FIG. 18 is a schematic view showing a partial structure of a flexible circuit board in a fourth form according to an embodiment of the present application;

FIG. 19 is a flow chart of a first method of forming a first recess in a conductive layer according to an embodiment of the present application;

FIG. 20 is a flow chart of a second method of forming a first recess on a conductive layer according to an embodiment of the present application;

FIG. 21 is a flow chart of a third method of forming a first recess on a conductive layer according to an embodiment of the present application;

fig. 22 is a schematic partial structure of a flexible circuit board in a fifth form in an embodiment of the application;

fig. 23 is a schematic partial structure of a flexible circuit board of a sixth form in the embodiment of the application;

fig. 24 is a schematic view showing a partial structure of a flexible circuit board of a seventh form in the embodiment of the application;

Fig. 25 is a schematic illustration of the bending process of a curved beam of a mechanically bistable beam from one stable state to another.

Wherein, the meanings represented by the reference numerals are respectively as follows:

10. a main frame; 11. an auxiliary frame; 12. a related base; 13. an associated shaft cover; 14. an associated door panel; 15. a reinforcing structure; 16. a shaft penetrating section;

100. a spindle mechanism; 101. a base; 102. a shaft cover; 103. a door panel; 104. reinforcing structural members; 105. a main board; 106. a sub-plate; 107. a connection region; 108. a fixed zone; 109. a non-fixed region; 110. a first subregion; 111. a second subregion; 112. a conductive structure layer; 113. a reinforcing layer; 114. a first additional layer; 115. a second additional layer; 116. a substrate layer; 117. a conductive layer; 118. a cover layer; 119. a first adhesive layer; 120. an adhesive layer; 121. a third additional layer; 122. a second hole; 123. a first side; 124. a second side; 125. a first concave groove; 126. a second adhesive layer; 127. a first wire; 128. a first sub-line; 129. a second sub-line; 130. a second wire; 131. a second concave groove; 132. a dry film; 133. a third concave groove; 200. a display screen; 201. a first portion; 202. a second portion; 203. a foldable portion; 301. a first sub-shell; 302. a second sub-shell; 400. and (5) bending the beam.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

It should be understood that references to "a plurality" in this disclosure refer to two or more. In the description of the present application, "/" means or, unless otherwise indicated, for example, A/B may represent A or B; "and/or" herein is merely an association relationship describing an association object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of the present application, the words "first", "second", etc. are used to distinguish the same item or similar items having substantially the same function and function. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

Referring to fig. 1 to 3, fig. 1 is a schematic structural diagram of an electronic device in a folded state according to an embodiment of the present application, fig. 2 is a schematic structural diagram of an electronic device in a semi-unfolded state according to an embodiment of the present application, and fig. 3 is a schematic structural diagram of an electronic device in an unfolded state according to an embodiment of the present application.

In one or more embodiments, the present application provides an electronic device, which may be a foldable electronic device; the electronic device comprises a shell and a rotating shaft mechanism 100, wherein the shell comprises a first sub-shell 301 and a second sub-shell 302, the first sub-shell 301 and the second sub-shell 302 are respectively connected with the rotating shaft mechanism 100, and the first sub-shell 301 and the second sub-shell 302 can rotate relatively through the rotating shaft mechanism 100. Exemplary electronic devices may be cell phones, tablet computers, notebooks, or electronic readers. The foldable electronic device is not limited to the electronic device with a foldable display screen, such as a mobile phone, but may be an electronic device that can be folded or unfolded between the display screen and a keyboard, for example: a notebook.

In the embodiment of the present application, taking an electronic device as an example of a mobile phone, the electronic device further includes a display screen 200, where the display screen 200 may be a flexible display screen, and the display screen 200 is respectively connected to the first sub-shell 301 and the second sub-shell 302. The first sub-housing 301 and the second sub-housing 302 may be a center of the cellular phone.

For convenience of description, a width direction of the foldable electronic device is defined as a B-B direction, a length direction of the foldable electronic device is defined as an A-A direction, and a thickness direction of the foldable electronic device is defined as a C-C direction. The A-A direction, the B-B direction and the C-C direction are perpendicular to each other. The width direction of the spindle mechanism 100 is parallel to the A-A direction, the width direction of the spindle mechanism 100 is parallel to the B-B direction, and the thickness direction of the spindle mechanism 100 is parallel to the C-C direction.

The foldable electronic device shown in fig. 1 is in a folded state, the foldable electronic device shown in fig. 2 is in a semi-unfolded state, and the foldable electronic device shown in fig. 3 is in an unfolded state. The unfolding angle α of the foldable electronic device shown in fig. 2 is 90 degrees, and the unfolding angle β of the foldable electronic device shown in fig. 3 is 180 degrees. The state of the electronic equipment is the same as that of the rotating shaft mechanism 100, namely when the foldable electronic equipment is in a folded state, the rotating shaft mechanism 100 is also in the folded state; when the foldable electronic device is in the semi-unfolded state, the rotating shaft mechanism 100 is also in the semi-unfolded state; when the foldable electronic device is in the unfolded state, the spindle mechanism 100 is also in the unfolded state.

It should be noted that the angles illustrated in the embodiments of the present application allow for a few deviations. For example, the angle α of expansion of the foldable electronic device shown in fig. 2 is 90 degrees, which means that α may be 90 degrees, or may be about 90 degrees, such as 80 degrees, 85 degrees, 95 degrees, or 100 degrees. The angle β of the foldable electronic device shown in fig. 3 is 180 degrees, which means that β may be 180 degrees, or may be about 180 degrees, such as 170 degrees, 175 degrees, 185 degrees, 190 degrees, etc. The angles illustrated hereinafter are to be understood identically.

Referring to fig. 4, fig. 4 is an exploded view of the electronic device shown in fig. 3, and fig. 4 only illustrates a position of the spindle mechanism 100, but the specific structure of the spindle mechanism 100 is not limited; the first sub-housing 301 and the second sub-housing 302 are respectively mounted on both sides of the spindle mechanism 100 in the B-B direction, and the display screen 200 includes a first portion 201, a second portion 202, and a foldable portion 203. Foldable portion 203 is positioned between first portion 201 and second portion 202, and foldable portion 203 may be folded in the A-A direction. The first portion 201, the second portion 202 and the foldable portion 203 together comprise the display screen 200. In this embodiment, the display screen 200 is a flexible display screen, for example, an organic light-emitting diode (OLED) display screen, an active-matrix organic light-emitting diode (AMOLED) display screen, a mini-led (mini organic lightemitting diode) display screen, a micro-led (micro organic light-emitting diode) display screen, a micro-organic led (micro organic light-emitting diode) display screen, and a quantum dot led (quantum dot light emitting diodes, QLED) display screen.

The display screen 200 is folded by the relative approach of the first sub-housing 301 and the second sub-housing 302, so that the foldable electronic device is folded. When the foldable electronic device is in the folded state, the foldable portion 203 of the display screen 200 is bent, and the first portion 201 and the second portion 202 are disposed opposite to each other. At this time, the display screen 200 is located between the first sub-case 301 and the second sub-case 302, so that the probability of damaging the display screen 200 can be greatly reduced, and effective protection of the display screen 200 can be achieved.

Referring to fig. 2 and fig. 4 together, the first sub-housing 301 and the second sub-housing 302 rotate relatively through the rotation shaft mechanism 100, and the first sub-housing 301 and the second sub-housing 302 are relatively far away from each other to drive the display screen 200 to be unfolded, so that the foldable electronic device is unfolded to a half-unfolded state. When the foldable electronic device is in the semi-unfolded state, the first sub-housing 301 and the second sub-housing 302 are unfolded to have an included angle α, and the first portion 201 and the second portion 202 are relatively unfolded and drive the foldable portion 203 to be unfolded. At this time, the angle between the first portion 201 and the second portion 202 is α.

Referring to fig. 3 and fig. 4 together, the first sub-housing 301 and the second sub-housing 302 are relatively rotated by the rotating shaft mechanism 100, and the first sub-housing 301 and the second sub-housing 302 are relatively far away from each other to further expand the display screen 200 until the foldable electronic device is flattened. The spindle mechanism 100 may have a damping mechanism to achieve a feel of opening and closing and state maintenance during rotation.

When the electronic device is in a flattened state, the angle between the first sub-housing 301 and the second sub-housing 302 is β. The foldable portion 203 is unfolded and the first portion 201 and the second portion 202 are unfolded relatively. At this time, the included angles between the first portion 201, the second portion 202 and the foldable portion 203 are β, and the display screen 200 has a large-area display area, so as to realize large-screen display of the foldable electronic device, and improve the use experience of the user.

It should be noted that, the included angle α and the included angle β are included angles between the first sub-housing 301 and the second sub-housing 302, which are only used to distinguish the angle between the first sub-housing 301 and the second sub-housing 302 of the foldable electronic device in different states. Wherein the included angle α is an angle between the first sub-housing 301 and the second sub-housing 302 when the foldable electronic device is in the semi-unfolded state; the included angle β refers to an angle between the first sub-housing 301 and the second sub-housing 302 in the unfolded state of the foldable electronic device.

FIG. 5 is a schematic diagram of a state of a flexible circuit board before destabilization in a foldable electronic device according to the related art; FIG. 6 is a schematic diagram of a state of the flexible circuit board after destabilization in a foldable electronic device according to the related art; referring to fig. 5 and 6, in a related art foldable electronic device, for example, a mobile phone, the foldable electronic device includes a main frame 10, a related rotation axis mechanism and a sub-frame 11, wherein the main frame 10 and the sub-frame 11 are rotatably connected through the related rotation axis mechanism, and a main board on the main frame 10 and a main board on the sub-frame 11 of the mobile phone are electrically connected through a flexible circuit board passing through the related rotation axis mechanism. The related rotating shaft mechanism comprises a related base 12, a related shaft cover 13 and a related door plate 14, wherein the related base 12 and the related shaft cover 13 are fixedly connected, and a flexible circuit board passes through between the related base 12 and the related shaft cover 13 and is fixed between the related base 12 and the related shaft cover 13; the associated door panel 14 is capable of rotating relative to the associated base 12 during folding and unfolding of the foldable electronic device. The flexible circuit board is fixed not only to the reinforcing structure 15 on the main frame 10 but also to the reinforcing structure 15 on the sub-frame 11, and also to the associated base 12 of the associated spindle mechanism, so that the portion of the flexible circuit board between the fixed position of the reinforcing structure 15 on the main frame 10 and the fixed position of the associated base 12 of the associated spindle mechanism, and the portion of the flexible circuit board between the fixed position of the reinforcing structure 15 on the sub-frame 11 and the fixed position of the associated base 12 of the associated spindle mechanism can be referred to as the through-shaft section 16 of the flexible circuit board. During folding and unfolding of the foldable electronic device, the position changes of the main frame 10, the auxiliary frame 11 and the related door panels 14 make the shaft penetrating section 16 have length redundancy, the influence of the flexible characteristics and related structures of the flexible circuit board can make the shaft penetrating section 16 form a plurality of arches, and the arches have instability risks of suddenly changing from upward bulge (indicated position of arrow X in fig. 5) to downward bulge (indicated position of arrow Y in fig. 6), and the risks can cause various reliability problems; in addition, as the foldable electronic device is lighter and thinner, the space left for the shaft penetrating section 16 in the thickness direction of the foldable electronic device is smaller and smaller, so that the shaft penetrating section 16 is easy to be unstable in the folding and unfolding processes of the related rotating shaft mechanism, the reliability of the shaft penetrating section 16 is affected, and the problems of stamping, abnormal sound and the like of a display screen are caused.

Therefore, in order to solve the problem that the through shaft section 16 of the flexible circuit board in the related art is prone to instability, the embodiment of the present application provides a flexible circuit board. The flexible circuit board provided by the embodiment of the application is explained in detail below.

FIG. 7 is a simplified schematic diagram of a flexible circuit board in a foldable electronic device in accordance with an embodiment of the application; referring to fig. 7, in some embodiments, the spindle mechanism 100 includes a base 101, a spindle cover 102, and a door panel 103; the base 101 is fixedly connected with the shaft cover 102, the door plate 103 is rotatably connected with the base 101 through a swing arm (not shown in the figure), and the first sub-shell 301 and the second sub-shell 302 are respectively and symmetrically arranged at two opposite sides of the rotating shaft mechanism 100; the first sub-shell 301 and the second sub-shell 302 are respectively connected with the base 101 in a rotating way through different swing arms; the flexible circuit board passes through the space between the base 101 and the shaft cover 102, and is fixed between the base 101 and the shaft cover 102, optionally, the flexible circuit board and the base 101 are fixed by back glue or glue; in the folded state of the foldable electronic device, the shaft cover 102 is in an exposed state. The flexible circuit board is also fixedly connected with the reinforced structural member 104 on the first sub-shell 301, and the flexible circuit board and the reinforced structural member 104 on the first sub-shell 301 can be fixedly connected by back glue or glue; the flexible circuit board is also fixedly connected with the reinforced structural member 104 on the second sub-shell 302, and the flexible circuit board can be fixedly connected with the reinforced structural member 104 on the second sub-shell 302 by back glue or glue; the reinforcing structure 104 may be a plate-like or sheet-like structure, and may be made of metal, plastic, or the like. The reinforcing structure 104 on the first sub-shell 301 and the first sub-shell 301 may be fixedly connected by means of gluing, welding or screwing. The reinforcing structure 104 on the second sub-shell 302 may be fixedly connected to the first sub-shell 301 by means of an adhesive, welding or screw connection. One end of the flexible circuit board in the length direction is electrically connected with the hard circuit board on the first sub-shell 301; the hard circuit board on the first sub-housing 301 may be the motherboard 105. The other end of the flexible circuit board in the length direction is electrically connected with the hard circuit board on the second sub-shell 302; the hard circuit board on the second sub-housing 302 may be the sub-board 106.

With continued reference to fig. 7, the flexible circuit board of fig. 7 includes a connection region 107, a fixed region 108, and a non-fixed region 109; the connection region 107, the fixed region 108, and the non-fixed region 109 are distributed along the length direction of the flexible circuit board; at least one of opposite ends of the non-fixed region 109 is connected with a fixed region 108, and the non-fixed region 109 can be bent and deformed; the non-fixed region 109 is a through-shaft section that is located between the reinforcing structure 104 and the base 101; the base 101 and the reinforcing structure 104 are fixedly connected to respective corresponding fixing areas 108, and the connection areas 107 realize electrical connection with the main board 105 and the sub-board 106. Illustratively, the number of attachment zones 107 is two, the number of non-fixed zones 109 is two, and the number of fixed zones 108 is three; the flexible circuit board has opposite head and tail ends, and two connection areas 107 are respectively located at the head and tail ends; of the three fixed areas 108, a first fixed area 108 is connected with the connecting area 107 at the head end, a second fixed area 108 is connected with the connecting area 107 at the tail end, two ends of the third fixed area 108 are respectively connected with two non-fixed areas 109, and the third fixed area 108 is positioned between the first fixed area and the second fixed area 108; one end of the connection region 107 at the head end is electrically connected to the hard circuit board on the first sub-case 301, and one end of the connection region 107 at the tail end is electrically connected to the hard circuit board on the second sub-case 302. It should be noted that, the number of the connection areas 107, the number of the non-fixed areas 109 and the number of the fixed areas 108 are not limited to the above-mentioned number, and the number of each area may be designed according to the actual situation to adapt to different types of electronic devices.

FIG. 8 is a schematic diagram of a partial structure of a flexible circuit board in a foldable electronic device in an embodiment of the application; only a part of the structure of the flexible circuit board between one reinforcing structure 104 and the base 101 is shown in fig. 8, and for a description of the part of the structure of the flexible circuit board between the other reinforcing structure 104 and the base 101, reference can be made to the description of fig. 8.

Referring to fig. 8, in some embodiments, two fixed regions 108 and one non-fixed region 109 are shown in fig. 8, wherein one fixed region 108 is fixed between the base 101 and the shaft cover 102 and the other fixed region 108 is fixed to the reinforcing structure 104; the two ends of the non-fixed region 109 in the longitudinal direction are connected to two fixed regions 108, respectively. The non-fixed area 109 includes a first sub-area 110 and a second sub-area 111, where the first sub-area 110 and the second sub-area 111 are distributed along the length direction of the flexible circuit board, the first sub-area 110 is connected to the second sub-area 111, and the stiffness of the first sub-area 110 is greater than the stiffness of the second sub-area 111. After the flexible circuit board is applied to the foldable electronic device, the fixed area 108 and the corresponding part of the foldable electronic device are fixed, the second sub-area 111 of the non-fixed area 109 is bent, the first sub-area 110 of the non-fixed area 109 is approximately linear, and in the unfolding and folding process of the foldable electronic device, the rigidity of the first sub-area 110 of the non-fixed area 109 is larger than that of the second sub-area 111, so that the first sub-area 110 is favorable for inhibiting the bistable state of the second sub-area 111, the occurrence of instability of the flexible circuit board is reduced, the reliability of the flexible circuit board is enhanced, and the problems of stamping and abnormal response of a display screen are not easy to occur.

In some embodiments, the number of second sub-areas 111 is a plurality, and the number of first sub-areas 110 is a plurality; in the length direction of the flexible circuit board, the plurality of second sub-areas 111 and the plurality of first sub-areas 110 in the non-fixed area 109 are alternately arranged, wherein the second sub-areas 111 are located between two adjacent first sub-areas 110, so that the plurality of first sub-areas 110 and the plurality of second sub-areas 111 can be arranged according to application scenes of different electronic devices, and the bistable state of the second sub-areas 111 can be better restrained by arranging the second sub-areas 111 between two adjacent first sub-areas 110, so that the occurrence of the phenomenon of instability of the flexible circuit board is reduced. Illustratively, one second sub-zone 111 is located between two adjacent first sub-zones 110.

It should be noted that, in the length direction of the flexible circuit board, the lengths of the plurality of first sub-areas 110 may be all different, may be the same, or at least two of them may be the same; the lengths of the different second sub-areas 111 may be different, may be the same, or at least two may be the same. The stiffness may be non-uniform for the plurality of first sub-regions 110, may be the same, or at least two may be the same; the stiffness may be non-uniform for the plurality of second sub-regions 111, may be the same, or at least two may be the same. The stiffness and length of the different first sub-zone 110 may thus be determined according to actual needs and the stiffness and length of the different second sub-zone 111 may be determined according to actual needs; as long as it is fulfilled that the stiffness of the second sub-zone 111 between two adjacent first sub-zones 110 is smaller than the stiffness of the two first sub-zones 110 on both sides of the second sub-zone 111.

The non-fixed zone 109 can be largely divided into: a straight line section near the base 101, a straight line section near the reinforcing structure 104, a circular arc section, and a straight line section between two adjacent circular arc sections. Wherein the length of the straight line section near the base 101 is 10% -20% of the length of the non-fixed region 109, and the length of the straight line section near the reinforcing structure 104 is 10% -20% of the length of the non-fixed region 109; and the length l=rγ of the circular arc area, where R is the radius of the circle corresponding to the circular arc area, γ is the radian corresponding to the circular arc of the circular arc area, γ is the radian after pi/6-pi/4 is taken from the left and right sides of the lowest point or the highest point of the circular arc area, i.e. the value range of γ is pi/3-pi/2, the length of the circular arc area is 10% -20% of the length of the non-fixed area 109, and the rest is the straight line area between two adjacent circular arc areas. For different circular arc areas, approximately one circle is corresponding, the radius of the circle is R, and when the number of the circular arc areas is 3, three circles are corresponding, namely, a circle O1, a circle O2 and a circle O3. It should be noted that the circular arc area may be circular arc or may be approximately circular arc; the straight line section area can be straight or approximately straight. For the straight line segment region it is the first sub-region 110 and the circular arc region is the second sub-region 111.

The number of regions into which the non-fixed region 109 is divided is related to the number of circular arc regions, the number of regions into which the non-fixed region 109 is divided is 2n+1, where n represents the number of circular arc regions, for example, when the circular arc region is 2, the number of regions into which the non-fixed region 109 is divided is 5, and the number of straight line segment regions, i.e., the first sub-region 110 is 3; the number of circular arc-shaped areas, i.e. the second sub-areas 111, is 2. When the circular arc area is 3, the number of the areas divided by the non-fixed area 109 is 7, wherein the number of the straight line segment areas, namely the first sub-area 110 is 4; the number of circular arc-shaped areas, i.e. the second sub-areas 111, is 3. When the number of the circular arc-shaped areas is 4, the number of the areas divided by the non-fixed area 109 is 9, wherein the number of the straight line segment areas, namely the first sub-areas 110 is 5; the number of circular arc-shaped areas, i.e. the second sub-areas 111, is 4.

Taking the non-fixed region 109, i.e. the through-shaft section has three circular arc regions as an example, the non-fixed region 109 may be divided into 7 regions, wherein the region a and the region g are straight line segment regions near the reinforcing structure 104, the region b, the region d and the region f are circular arc regions, and the region c and the region e are middle straight line segment regions. Region a, region c, region e and region g are the regions where the increased bending stiffness has the most pronounced effect on improving the instability of the through-shaft section. Region a, region c, region e and region g are respectively first sub-region 110, and region b, region d and region f are respectively second sub-region 111.

With continued reference to fig. 8, in some embodiments, the non-fixed regions 109 are respectively located at two ends of the first sub-region 110; as shown in fig. 8, the region a and the region g are located at both ends of the non-fixed region 109; since the fixed region 108 is connected with the non-fixed region 109, and the fixed region 108 is fixed with the corresponding component of the foldable electronic device, the first sub-region 110 is connected with the fixed region 108, which is beneficial to reducing the occurrence of instability of the whole non-fixed region 109.

FIG. 9 is a schematic view showing a partial structure of a flexible circuit board of a first form in an embodiment of the present application; referring to fig. 9, in some embodiments, the flexible circuit board includes a conductive structure layer 112 and a reinforcing layer 113 stacked in a thickness direction of the flexible circuit board; the stiffening layer 113 is arranged at the fixed region 108, and the conductive structure layer 112 covers the fixed region 108 and the non-fixed region 109. The reinforcing layer 113 is utilized to enhance the mechanical strength and stability of the flexible circuit board, and improve the reliability and service life of the flexible circuit board; while the conductive structure layer 112 can realize the transmission of electric signals and be used as the conduction and grounding of a power supply. In addition, the reinforcing layer 113 is disposed in the fixing area 108, which is beneficial for the fixing area 108 to be fixedly connected with the base 101 or the reinforcing structural member 104 of the foldable electronic device. Illustratively, in fig. 9, the non-fixed region 109 has three circular arc regions, which are divided into 7 regions, the region a, the region c, the region e, and the region g being the first sub-region 110, respectively, and the region b, the region d, and the region f being the second sub-region 111, respectively. It should be noted that the conductive structure layer 112 of the flexible circuit board also covers the connection region 107 of the flexible circuit board. After the flexible circuit board is flattened and straightened, the length direction of the flexible circuit board is parallel to the width direction of the electronic equipment, the thickness direction of the flexible circuit board is parallel to the thickness direction of the electronic equipment, and the width direction of the flexible circuit board is parallel to the length direction of the electronic equipment. The material of the reinforcing layer 113 may be polyimide, PED, glass fiber epoxy, steel sheet, or glass fiber cloth.

With continued reference to fig. 9, in some embodiments, the flexible circuit board further includes a first additional layer 114, the first additional layer 114 being located in the first sub-region 110; at least one of the opposite sides of the conductive structure layer 112 is provided with a first additional layer 114. Thus, the first sub-area 110 is more than the second sub-area 111 by the first additional layer 114, so that the rigidity of the first sub-area 110 is greater than that of the second sub-area 111, so as to reduce the occurrence of instability of the flexible circuit board. The first additional layer 114 and the stiffening layer 113 are located on the same side of the conductive structure layer 112 in the thickness direction of the flexible circuit board, or the first additional layer 114 and the stiffening layer 113 are respectively located on opposite sides of the conductive structure layer 112, which may be specifically determined as needed. And it may be provided on at least one of the opposite sides of the conductive structure layer 112 for the reinforcing layer 113, for example, on only one side, or on both sides. In addition, to ensure structural stability of the flexible circuit board during use, the first additional layers 114 of the plurality of different first sub-regions 110 are all located on the same side of the conductive structure layer 112. Of course, in some other possible embodiments, at least one first additional layer 114 may be disposed on a different side of the other first additional layer 114 than the first additional layer 114 in the plurality of different first sub-regions 110. Illustratively, as shown in FIG. 9, regions a, c, e, and g each have a first additional layer 114; the number of conductive structure layers 112 is one.

Since the first additional layer 114 is located in the first sub-area 110, it is possible to realize that the cross-sectional area of the first sub-area 110 is larger than the cross-sectional area of the second sub-area 111, the cross-sectional area of the first sub-area 110 is parallel to the thickness direction and the width direction of the flexible circuit board, respectively, and the cross-sectional area of the second sub-area 111 is parallel to the thickness direction and the width direction of the flexible circuit board, respectively, so that the stiffness of the first sub-area 110 is larger than the stiffness of the second sub-area 111 by making the cross-sectional area of the first sub-area 110 larger than the cross-sectional area of the second sub-area 111. The cross section of the first sub-area 110 and the cross section of the second sub-area 111 cannot be the cross section at the boundary between the first sub-area 110 and the second sub-area 111.

In some embodiments, the material of the first additional layer 114 is foam, polyester resin, fiberglass cloth, or polyimide. In this way, different types of materials can be selected according to the application scenario that is not needed, so as to meet the requirement that the rigidity of the first sub-zone 110 is greater than that of the second sub-zone 111. Of course, a low stiffness, low density material may also be selected for the first additional layer 114 to reduce the risk of stress concentrations. The length of the first additional layer 114 in the length direction of the flexible circuit board does not exceed the length of the first sub-area 110; the length of the first sub-area 110 may be 15% of the length of the non-fixed area 109, which may improve the anti-destabilization performance of the flexible circuit board.

FIG. 10 is a schematic view of a part of a flexible circuit board in a second form of embodiment of the application; referring to fig. 10, in some embodiments, when the circular arc-shaped area is 2, the number of areas into which the non-fixed area 109 is divided is 5, wherein the number of the first sub-areas 110 is 3; the number of the second sub-areas 111 is 2; the number of conductive structure layers 112 is one; the first additional layer 114 is located in the first sub-region 110, the stiffening layer 113 is located in the fixed region 108, and the first additional layer 114 and the stiffening layer 113 are located on opposite sides of the conductive structure layer 112, respectively.

FIG. 11 is a schematic view showing a partial structure of a flexible circuit board according to a third form of the embodiment of the present application; referring to fig. 11, in some embodiments, the number of conductive structure layers 112 is plural, and the plurality of conductive structure layers 112 are stacked in the thickness direction of the flexible circuit board. Thus, when the number of the conductive structure layers 112 is plural, a flexible circuit board with high density and high signal-to-noise ratio is formed, which has good anti-interference and anti-electromagnetic wave interference capability. A stiffening layer 113 is disposed on two adjacent conductive structure layers 112, and the stiffening layer 113 is located in the fixed region 108. The flexible circuit board further comprises a second additional layer 115, wherein a second additional layer 115 is arranged between two adjacent conductive structure layers 112, and the second additional layer 115 is located in the first sub-area 110, such that the second additional layer 115 is located in the first sub-area 110, and the second sub-area 111 is free of the second additional layer 115, and the second sub-area 111 is in the form of a void, i.e. an air gap is arranged between two adjacent conductive structure layers 112 in the second sub-area 111, and no solid structure is present, such that the stiffness of the first sub-area 110 is greater than the stiffness of the second sub-area 111. Illustratively, in fig. 11, the number of conductive structure layers 112 is three; region a, region c, region e and region g each have a second additional layer 115; and since the second additional layer 115 is located in the first sub-zone 110, it can be achieved that the area of the cross-section of the first sub-zone 110 is larger than the area of the cross-section of the second sub-zone 111. The length of the second additional layer 115 in the length direction of the flexible circuit board does not exceed the length of the first sub-area 110; the length of the first sub-area 110 may be 15% of the length of the non-fixed area 109, which may improve the anti-destabilization performance of the flexible circuit board.

It should be noted that, in other possible embodiments, a layer structure having a stiffness smaller than that of the second additional layer 115 may be disposed between two adjacent conductive structure layers 112 in the second sub-region 111.

In some embodiments, the material of the second additional layer 115 is foam, polyester resin, fiberglass cloth or polyimide, so that different types of materials can be selected according to the application scenario, so as to meet the requirement that the rigidity of the first sub-area 110 is greater than that of the second sub-area 111. Of course, a low stiffness, low density material may also be selected for the first additional layer 114 to reduce the risk of stress concentrations. The material of the second additional layer 115 may be the same as or different from the material of the stiffening layer 113.

FIG. 12 is a schematic flow chart of a method for manufacturing a flexible circuit board with a plurality of conductive structure layers 112 according to an embodiment of the present application, wherein only the non-fixing area 109 of the flexible circuit board is shown in FIG. 12; referring to fig. 12, in some embodiments, the conductive structure layer 112 includes a base material layer 116, a conductive layer 117, and a cover layer 118, and the cover layer 118, the conductive layer 117, and the base material layer 116 are sequentially stacked in the thickness direction of the flexible circuit board. The cover layer 118 protects the conductive layer 117 and prevents the conductive layer 117 from being corroded and damaged by the external environment; the conductive layer 117 can be used for transmitting an electric signal and conducting and grounding a power supply. The substrate layer 116 serves as a main support portion of the flexible circuit board, which has insulating properties. A first glue layer 119 may be provided between the substrate layer 116 and the conductive layer 117 to enable connection between the substrate layer 116 and the conductive layer 117. The material of the base layer 116 may be polyimide, the material of the conductive layer 117 may be copper, and the material of the cover layer 118 may be polyimide. The adhesive layer 120 is disposed on the cover layer 118 of the conductive structure layer 112 in fig. 12 (h), and after the adhesive layer 120 in fig. 12 (h) is windowed, referring to fig. 12 (i), the adhesive layer 120 remaining on the first sub-region 110 forms the second additional layer 115, and the adhesive layer 120 on the second sub-region 111 disappears due to the windowing operation, so that the second additional layer 115 is not formed on the second sub-region 111. Finally, another conductive structure layer 112 is arranged on the bonding layer 120, so that the flexible circuit board with the second additional layer 115 between the two conductive structure layers 112 of the flexible circuit board is realized, as can be seen in fig. 12 (j); in fig. 12, the second additional layer 115 on each first sub-region 110 is the same material. Illustratively, in fig. 12, the number of conductive structure layers 112 is two, the number of first sub-regions 110 is 4, and the number of second sub-regions 111 is 3. In fig. 12, 115 is also indicated by brackets beside the reference numeral 120 in the (i) and (j) diagrams, which indicate that the adhesive layer 120 located on the first sub-area 110 is the second additional layer 115.

FIG. 13 is a schematic view of another process for manufacturing a flexible circuit board having a plurality of conductive structure layers 112 according to an embodiment of the present application; the method of forming the second additional layer 115 in fig. 13 is different from the method of forming the second additional layer 115 in fig. 12; the material of the second additional layer 115 on each of the first sub-regions 110 in fig. 13 is not exactly the same. Only the non-fixed area 109 of the flexible circuit board is shown in fig. 13; the adhesive layer 120 is provided on the cover layer 118 of the conductive structure layer 112 in fig. 13 (h), and after the adhesive layer 120 in fig. 13 (h) is fully windowed, the two ends in the longitudinal direction of the non-fixed region 109 are the adhesive layers 120 remaining after the full windowed, and the remaining adhesive layers 120 form the second additional layer 115; after the full window, the design area is attached to the second adhesive layer 126 with two adhesive sides, and in order to reduce stress concentration, a compressible second adhesive layer 126 with lower rigidity, such as a foam adhesive layer, can be used, as shown in fig. 13 (i); finally, another conductive structure layer 112 is disposed on the adhesive layer 120 and the second adhesive layer 126, thereby realizing a flexible circuit board having the second additional layer 115 between the two conductive structure layers 112 of the flexible circuit board, as can be seen in fig. 13 (j). Illustratively, in fig. 13, the number of conductive structure layers 112 is two, the number of regions into which the non-fixed region 109 is divided is 9, and the number of first sub-regions 110 is 5; the number of the second sub-areas 111 is 4; the first sub-region 110 has a second additional layer 115 formed thereon, while the second sub-region 111 is located without the second additional layer 115.

Fig. 14 is a schematic view showing a first form of the windowing method for the adhesive layer 120 in the embodiment of the present application; using the fenestration method of fig. 14, a flexible circuit board having a plurality of conductive structure layers 112 can be manufactured; FIG. 14 is a top view of a circuit board in an embodiment of the application; in some embodiments, after the adhesive layer 120 is windowed in fig. 14, the second sub-area 111 is free of the adhesive layer 120, i.e. such that the second sub-area 111 is in the form of an air gap, while the first sub-area 110 still has the adhesive layer 120, thereby forming the second additional layer 115. In addition, the fabrication of the flexible circuit board of fig. 12 and 13 having a plurality of conductive structure layers 112 may take the form of windowing as described in fig. 14. Illustratively, the non-fixed zone 109 in FIG. 14 is divided into 7 zones, with zone a, zone c, zone e, and zone g each having a second additional layer 115; and regions b, d and f are in the form of air gaps, without adhesive layer 120. Also shown in fig. 14 is a flexible circuit board mounting region 108. The adhesive layer 120 is also referred to as a Bonding Sheet adhesive layer.

Fig. 15 is a schematic view of a second form of the windowing mode for the adhesive layer 120 in the embodiment of the present application; using the fenestration method of fig. 15, a flexible circuit board having a plurality of conductive structure layers 112 can be manufactured; fig. 15 is a top view of a circuit board in an embodiment of the application. Fig. 16 is a schematic view of a third form of windowing mode for the adhesive layer 120 in the embodiment of the present application; using the fenestration method of fig. 16, a flexible circuit board having a plurality of conductive structure layers 112 can be manufactured; fig. 16 is a top view of a circuit board in an embodiment of the application. Fig. 17 is a schematic view of a fourth form of the windowing method for the adhesive layer 120 in the embodiment of the present application; using the fenestration method of fig. 17, a flexible circuit board having a plurality of conductive structure layers 112 can be manufactured; fig. 17 is a top view of a circuit board in an embodiment of the application. Fig. 15, 16 and 17 also illustrate the structure of different forms of flexible circuit boards in embodiments of the application, and each illustrates a fixed region 108 and a non-fixed region 109 of the flexible circuit board.

In some embodiments, referring to fig. 15, 16 and 17, in some embodiments, the flexible circuit board further includes a third additional layer 121, a third additional layer 121 is further disposed between two adjacent conductive structure layers 112, and the third additional layer 121 is located in the second sub-region 111; the orthographic projection area of the third additional layer 121 in the second plane is smaller than the orthographic projection area of the second sub-area 111 in the second plane, and the second plane is parallel to the length direction and the width direction of the flexible circuit board, respectively, so that the third additional layer 121 covers a part of the second sub-area 111 (i.e. the third additional layer 121 does not cover the second sub-area 111 completely), the second additional layer 115 covers the whole of the first sub-area 110, and the rigidity of the first sub-area 110 is higher than the rigidity of the second sub-area 111. The adhesive layer 120 forms a third additional layer 121. It should be noted that any one of the planes parallel to the longitudinal direction and the width direction of the flexible circuit board, respectively, may be the second plane, that is, the second plane does not mean the only plane. The third additional layer 121 is provided with at least one second hole 122, which is achieved by providing the third additional layer 121 with the second hole 122, so that the situation that the stress of the non-solid area is too concentrated can be avoided, and the rigidity of the first sub-area 110 can be made to be greater than that of the second sub-area 111. The number of the second holes 122 may be 1 or more, and the shape and size of the second holes 122 and the arrangement of the plurality of second holes 122 on the third additional layer 121 may be determined according to practical situations. The number of the second holes 122 of the third additional layer 121 on the second sub-area 111 is 1 or more, for example, 1, 2, 3, 4, 5, etc., and when the number of the second holes 122 is plural, the plurality of second holes 122 are spaced apart along the width direction of the flexible circuit board, and the shape of the second holes 122 is polygonal, circular, or elliptical, for example, the polygon may be triangle, rectangle, pentagon, etc. Illustratively, the number of the second holes 122 of the third additional layer 121 on the second sub-area 111 in fig. 15 is 1, and the shape of the second holes 122 is rectangular; in fig. 16, the number of the second holes 122 of the third additional layer 121 on the second sub-area 111 is 4, and the shape of the second holes 122 is rectangular. In fig. 17, the number of the second holes 122 of the third additional layer 121 on the second sub-area 111 is plural, and the plural second holes 122 are communicated with each other; this causes the plurality of second holes 122 to communicate in a grid-like fashion. In fig. 15, 16 and 17, the non-fixed zone 109 is divided into 7 zones, wherein zone a, zone c, zone e and zone g each have a second additional layer 115; and each of the region b, the region d and the region f has a third additional layer 121, and the material of the second additional layer 115 may be the same as that of the third additional layer 121; the adhesive layer 120 in the first sub-area 110 forms a second additional layer 115 and the adhesive layer 120 in the second sub-area 111 forms a third additional layer 121.

In summary, as can be seen from fig. 14, 15, 16 and 17, in the embodiment of the present application, the method of windowing the adhesive layer 120 located in the second sub-area 111 by completely removing, partially removing, removing in a grid manner, removing in a fence manner, and the like is adopted, so that the rigidity of the first sub-area 110 is greater than the rigidity of the second sub-area 111, thereby meeting the design requirements of the flexible circuit board in different application scenarios.

It should be noted that, in some other possible embodiments, the number, shape and size of the upper holes of the third additional layer 121 on the different second sub-areas 111 may be the same or different, and may be specifically determined according to practical situations. In addition, as in fig. 15 to 17, the windowing method for the adhesive layer 120 may be applied to the case of a flexible circuit board having a single conductive structure layer 112, and the first additional layer 114 and/or the third additional layer 121 may be formed by using the windowing method for the adhesive layer 120. The windowing of any of the forms of fig. 15, 16 and 17 may also be employed for the fabrication of flexible circuit boards having multiple conductive structure layers 112 in fig. 12 and 13.

In some embodiments, the material of the third additional layer 121 is foam, polyester resin, fiberglass cloth or polyimide, so that different types of materials can be selected according to the application scenario, so as to meet the requirement that the rigidity of the first sub-area 110 is greater than that of the second sub-area 111. Of course, a material with low stiffness and low density may be chosen for the third additional layer 121 to reduce the risk of stress concentrations.

FIG. 18 is a schematic view showing a partial structure of a flexible circuit board in a fourth form according to an embodiment of the present application; the flexible circuit board in fig. 18 shows a fixed region 108 and a non-fixed region 109. Referring to fig. 18, in some embodiments, the conductive layer 117 has opposite first and second sides 123, 124; the reinforcing layer 113 is located on the side where the first side 123 of the conductive layer 117 is located, or/and the reinforcing layer 113 is located on the side where the second side 124 of the conductive layer 117 is located, so that the reinforcing layer 113 is disposed on at least one side of the conductive layer 117 opposite to the first side 123 and the second side 124, and thus the reinforcing layer 113 can be fixed with a corresponding component in the electronic device, so that the conductive layer 117 is indirectly fixed with the corresponding component in the electronic device, and the possibility of damaging the flexible circuit board during assembly and maintenance is reduced. Illustratively, in fig. 18 both the substrate layer 116 and the stiffening layer 113 are located on the side of the first side 123 of the conductive layer 117; the base material layer 116 is located between the stiffening layer 113 and the conductive layer 117; the base material layer 116 and the reinforcing layer 113 are fixedly connected, and the base material layer 116 and the conductive layer 117 are fixedly connected.

Referring to fig. 18, in some embodiments, the conductive layer 117 has at least one first concave groove 125, where the first concave groove 125 is located in the second sub-area 111, and the first concave groove 125 is directly formed on the conductive layer 117 located in the second sub-area 111, and is not formed on the conductive layer 117 located in the first sub-area 110, or the depth of the groove formed in the conductive layer 117 located in the first sub-area 110 is smaller than that of the first concave groove 125, so that the area of the cross section of the first sub-area 110 may be larger than that of the cross section of the second sub-area 111, so that the rigidity of the first sub-area 110 is larger than that of the second sub-area 111, thereby reducing the occurrence of instability of the flexible circuit board. The number of the first concave grooves 125 on the second sub-area 111 may be 1 or more, and may be specifically determined according to practical situations. Illustratively, referring to FIG. 18, each of the second sub-regions 111 has a first recessed channel 125 disposed therein; the width of the first concave groove 125 extends along the length direction of the flexible circuit board, and the length of the first concave groove 125 extends along the width direction of the flexible circuit board; in fig. 18, the non-fixed region 109 is divided into 7 regions, wherein each of the region b, the region d, and the region f is provided with the first concave groove 125, and the region a, the region c, the region e, and the region g are not provided with the first concave groove 125.

Fig. 19 is a flow chart of a first manufacturing method of forming the first concave groove 125 on the conductive layer 117 in the embodiment of the application; in fig. 19, the first recess 125 is formed by thinning the conductive layer 117 to manufacture a flexible circuit board according to an embodiment of the present application. Fig. 20 is a flow chart of a second manufacturing method of forming the first concave groove 125 on the conductive layer 117 in the embodiment of the application; in fig. 20, a first concave groove 125 is formed by thickening the conductive layer 117 to manufacture a flexible circuit board according to an embodiment of the present application. Fig. 21 is a flow chart of a third manufacturing method of forming the first concave groove 125 on the conductive layer 117 in the embodiment of the application; the first recess 125 is formed by reducing the thickness of the conductive layer 117 in fig. 21 to manufacture a flexible circuit board according to an embodiment of the present application, and fig. 19, 20 and 21 also show structures of different forms of flexible circuit boards according to embodiments of the present application, and fig. 19, 20 and 21 show only a portion of the non-fixing region 109 of the flexible circuit board; referring to fig. 19 (k), 20 (k), and 21 (m), in some embodiments, a second glue layer 126 may be provided between the cover layer 118 and the conductive layer 117 to enable connection between the cover layer 118 and the conductive layer 117. Referring to fig. 21 (m), in some embodiments, the first concave groove 125 is stepped in the thickness direction of the flexible circuit board, so that the rigidity of different positions of the second sub-area 111 is gradually changed to meet the requirements of different application scenarios, thereby reducing the occurrence of instability of the flexible circuit board.

Referring to fig. 19, fig. 19 (h) is a flexible circuit board having a base material layer 116 and a conductive layer 117 after a drilling process, a black hole copper plating process; fig. 19 (i) is a flexible circuit board having a base material layer 116 and a conductive layer 117 after a dry film 132 and exposure developing process; fig. 19 (j) is a flexible circuit board having a substrate layer 116 and a conductive layer 117 after a microetching process and a stripping process, wherein the thinning of the conductive layer 117 located in the second sub-region 111 is achieved through the microetching process to form a first concave groove 125; fig. 19 (k) is a schematic structural view of a flexible circuit board formed after the second adhesive layer 126 and the cover layer 118 are disposed, and the flexible circuit board having the first concave groove 125 formed on the conductive layer 117 is subjected to the method shown in fig. 19 (h) to (k).

Referring to fig. 20, fig. 20 (h) is a flexible circuit board having a base material layer 116 and a conductive layer 117 after a drilling process, a black hole copper plating process; fig. 20 (i) is a flexible circuit board having a base layer 116 and a conductive layer 117, to which a dry film 132 of a specific pattern is attached; fig. 20 (j) shows a flexible circuit board having a substrate layer 116 and a conductive layer 117 after being subjected to a pattern plating process, wherein the thickening of the conductive layer 117 located in the first sub-region 110 is achieved through the pattern plating process to form a first recess 125; fig. 20 (k) is a schematic structural view of a flexible circuit board formed by a film removing process, an etching circuit process, and the provision of the second adhesive layer 126 and the cover layer 118, and the flexible circuit board is formed with the first recess 125 on the conductive layer 117 by the method shown in fig. 20 (h) to (k).

Referring to fig. 21, fig. 21 (h) is a flexible circuit board having a base material layer 116 and a conductive layer 117 after a drilling process, a black hole copper plating process; fig. 21 (i) shows a flexible circuit board having a base material layer 116 and a conductive layer 117 after the dry film 132 is applied; fig. 21 (j) is a flexible circuit board having a base material layer 116 and a conductive layer 117 after copper plating, wherein thickening of the conductive layer 117 located in the first sub-region 110 is achieved through a copper plating process to form a first recess 125, and further, control of the thickness of the copper plating can be achieved by controlling the magnitude of current in the copper plating process; fig. 21 (k) is a schematic structural diagram of a flexible circuit board having a base layer 116 and a conductive layer 117 after the copper plating process of fig. 21 (j) is performed, the original dry film 132 is removed, a new dry film 132 is attached, fig. 21 (l) is a flexible circuit board having a base layer 116 and a conductive layer 117 after copper plating is performed, wherein the conductive layer 117 is thickened by the copper plating process again to form a stepped first concave groove 125, and the processes from fig. 21 (k) to fig. 21 (l) are repeated, namely, the original dry film 132 is removed, the new dry film 132 is attached again, and the copper plating process is repeated until the shape of the required first concave groove 125 is obtained, and then the required flexible circuit board is obtained through the film removing process, the circuit etching process, and the arrangement of a second adhesive layer 126 and a cover layer 118.

Note that, the flexible circuit board in fig. 18 may be manufactured by a method of forming the first concave groove 125 in the conductive layer 117 in any of fig. 19, 20, or 21; in addition, with respect to the method of forming the first recess 125 on the conductive layer 117 in any of fig. 19, 20 or 21, the thickness of the conductive layer 117 in the second sub-region 111 is made smaller than the thickness of the conductive layer 117 in the first sub-region 110 in the second sub-region 111, so that the rigidity of the second sub-region 111 is changed so that the rigidity of the first sub-region 110 is greater than the rigidity of the second sub-region 111. Fig. 21 illustrates that the conductive layer 117 in the first sub-region is thickened by electroplating, so that a first recess 125 having a stepped shape is formed in the second sub-region; in some other possible embodiments, the conductive layer 117 in the second sub-region may be gradually thinned, so that the first recess 125 is formed in the second sub-region in a stepped shape.

In the related art, the thickness of the conductive copper layer in the flexible circuit board in the length direction and the width direction of the flexible circuit board is uniform, and is generally 6 micrometers to 12 micrometers; in order to solve the instability problem of the shaft penetrating segment 16 in the related art, the embodiment of the present application may use a manner of thickening the thickness of the conductive layer 117 located in the first sub-region 110, or/and a manner of thinning the thickness of the conductive layer 117 located in the second sub-region 111.

First, the manner of thinning (see fig. 19): the thickness of the conductive layer 117 located in the second sub-region 111 is 1/2 of the thickness of the copper layer in the related art, and the length of the second sub-region 111 is not more than 13.3% -14% of the length of the non-fixed region 109; the smaller the thickness of the conductive layer 117 in the second sub-region 111 than the thickness of the conductive layer 117 in the first sub-region 110, the better the resistance to instability, with the width and length of the conductive layer 117 in the second sub-region 111 unchanged. In addition, when the thickness of the conductive layer 117 located in the second sub-region 111 is smaller, the width and/or length of the conductive layer 117 located in the second sub-region 111 may be reduced accordingly. The thickness of the conductive layer 117 located in the first sub-region 110 may be 9% -9.3% of the thickness of a flexible circuit board having only a single conductive structure layer 112.

Second, the thickening means (see fig. 20 and 21): making the thickness of the conductive layer 117 located in the first sub-region 110 2 times the thickness of the copper layer in the related art, and the length of the first sub-region 110 may be greater than or equal to 15% of the length of the non-fixed region 109; the greater the thickness of the conductive layer 117 in the first sub-region 110 than the thickness of the conductive layer 117 in the second sub-region 111, the better the resistance to instability, with the width and length of the conductive layer 117 in the first sub-region 110 unchanged. In addition, when the thickness of the conductive layer 117 located in the first sub-region 110 is greater, the width and/or length of the conductive layer 117 located in the first sub-region 110 may be reduced accordingly. The thickness of the conductive layer 117 in the first sub-region 110 may be 18.6% -19% of the thickness of a flexible circuit board having only a single conductive structure layer 112.

It should be noted that, the technical solution for changing the thickness of the conductive layer 117 may be applied not only to the shaft penetrating section of the flexible circuit board in the foldable electronic device, but also to the circuit board at other positions in the electronic device, for example, the flexible circuit board connecting the motherboard 105 and the small board in the mobile phone, and the thickness may be changed according to different functions of the conductive wires in the conductive layer 117, for example: the signal line is thickened, and the charging and discharging power line is thinned. The method for thinning or thickening the thickness of the conductive layer made of copper material can be realized by a microetching process, a pattern etching process, an improved semi-addition process, an electroplating process or the like. In addition, in some other possible embodiments, the substrate layer 116 and/or the cover layer 118 may be designed to have a stiffness of the first sub-region 110 greater than a stiffness of the second sub-region 111 by designing the conductive layer 117 as described above.

Fig. 22 is a schematic partial structure of a flexible circuit board according to a fifth form of the embodiment of the application, and fig. 22 is a plan view of the flexible circuit board; fig. 23 is a schematic partial structure of a flexible circuit board according to a sixth form of the embodiment of the application, and fig. 23 is a plan view of the flexible circuit board; fig. 22 and 23 show the fixed region 108 and the non-fixed region 109 of the flexible circuit board; as shown in connection with fig. 22 and 23, in some embodiments the stiffness of the first sub-zone 110 may be made larger than the stiffness of the second sub-zone 111 by a change of the total weight of the conductive layer 117 over the second sub-zone 111. The conductive layer 117 includes at least one first conductive line 127, a portion of the first conductive line 127 located in each first sub-region 110 may be referred to as a first sub-line 128, and a portion of the first conductive line 127 located in each second sub-region 111 may be referred to as a second sub-line 129, and the first sub-line 128 is electrically connected to the second sub-line 129; the orthographic projection area of the second sub-line 129 in the first plane is smaller than that of the first sub-line 128 in the first plane, and the first plane is parallel to the length direction and the width direction of the flexible circuit board respectively, so that different functions, such as transmission of electric signals and conduction and grounding as a power supply, are realized by using different first conducting wires 127. Meanwhile, in the at least one first conducting wire 127, the first sub-line 128 and the second sub-line 129 of the at least one first conducting wire 127 are designed so that the rigidity of the first sub-region 110 is higher than that of the second sub-region 111 after the orthographic projection area of the second sub-line 129 on the same first conducting wire 127 is smaller than that of the first sub-line 128. It should be noted that any one of the planes parallel to the longitudinal direction and the width direction of the flexible circuit board, respectively, may be the first plane, that is, the first plane does not mean the only plane. The number of the first wires 127 is two, and the two first wires 127 are distributed at intervals along the width direction of the flexible circuit board; one of the first conductive lines 127 is a ground line, and the other first conductive line 127 is a power line. Illustratively, referring to fig. 22, in the width direction of the flexible circuit board, the width of the first sub-line 128 is made larger than the width of at least part of the structure of the second sub-line 129, so that the rigidity of the first sub-area 110 is greater than the rigidity of the second sub-area 111 after the orthographic projection area of the second sub-line 129 on the same first conductive line 127 is made smaller than the orthographic projection area of the first sub-line 128. As yet another example, referring to fig. 23, the second sub-line 129 has at least one first hole thereon, and when the number of the first holes on the second sub-line 129 is plural, the second sub-line 129 is made to have a mesh structure; in addition, the first sub-line 128 is of a solid structure, so that the rigidity of the first sub-area 110 is greater than the rigidity of the second sub-area 111 after the orthographic projection area of the second sub-line 129 on the same first conducting wire 127 is smaller than the orthographic projection area of the first sub-line 128.

It should be noted that, in some other possible embodiments, on the same first conductive line 127, the width of the first sub-line 128 on a part of the first sub-area 110 may be made larger than the width of the second sub-line 129 on a part of the second sub-area 111; the second sub-line 129 of another part of the first sub-area 110 may be provided with a first hole, so that the second sub-line 129 is in a grid shape, so as to realize that the rigidity of the first sub-area 110 is greater than that of the second sub-area 111.

With continued reference to fig. 22 and 23, the conductive layer 117 further includes at least one second conductive line 130, where the second conductive line 130 is spaced apart from the first conductive line 127; illustratively, the number of second conductors 130 is a plurality, and the second conductors 130 may be signal lines to enable communication through the flexible circuit board, with the second conductors 130 being located between the two first conductors 127.

Fig. 24 is a schematic view showing a partial structure of a flexible circuit board of a seventh form in the embodiment of the present application, and fig. 24 shows a fixed region 108 and a non-fixed region 109 of the flexible circuit board. Referring to fig. 24, in some embodiments, at least one of the substrate layer 116, the cover layer 118, and the second glue layer 126 in the conductive structure layer 112 may be slotted in a portion of the second sub-region 111 to achieve a stiffness of the first sub-region 110 that is greater than a stiffness of the second sub-region 111.

As shown in fig. 24, the substrate layer 116 has at least one second concave groove 131, i.e. the number of second concave grooves 131 on the substrate layer 116 is plural, and different second concave grooves 131 are located in different second sub-areas 111, so that the substrate layer 116 located in the second sub-areas 111 is provided with the second concave grooves 131, so that the rigidity of the first sub-areas 110 is greater than the rigidity of the second sub-areas 111, which is beneficial to the processing and manufacturing of the flexible circuit board. The cover layer 118 has at least one third recess 133, i.e. the number of the third recess 133 is plural, the plural different third recess 133 are located in different second sub-areas 111, and the cover layer 118 located in the second sub-area 111 is provided with the third recess 133, so that the rigidity of the first sub-area 110 is greater than the rigidity of the second sub-area 111, which is beneficial to the processing and manufacturing of the flexible circuit board. The length of the second sub-zone 111 may be more than 13% of the length of the non-fixed zone 109; the length of the second recess groove 131 in the length direction of the flexible circuit board is not greater than the length of the second sub-area 111, and the length of the third recess groove 133 in the length direction of the flexible circuit board is not greater than the length of the second sub-area 111. The second adhesive layer 126 has at least one third concave groove 133, i.e. the number of third concave grooves 133 is plural, and plural different third concave grooves 133 are located in different second sub-areas 111; the third recess groove 133 on the second adhesive layer 126 may be a groove penetrating through opposite surfaces of the second adhesive layer 126 in the thickness direction. After the second recess 131 is formed in the substrate layer 116, the thickness of the substrate layer 116 in the second sub-region 111 may be 1/2 of the thickness of the substrate layer 116 in the first sub-region 110; the length of the second sub-zone 111 may be no more than 13.3% of the length of the non-fixed zone 109. After the cover layer 118 is provided with the second concave groove 131, the thickness of the cover layer 118 of the second sub-region 111 may be 1/2 of the thickness of the cover layer 118 of the first sub-region 110; the length of the second sub-zone 111 may be no more than 13.3% of the length of the non-fixed zone 109.

FIG. 25 is a schematic illustration of a bending process of a curved beam 400 of a mechanically bistable beam from one stable state to another; according to the theory of mechanical bistable Liang Moxing, bistable beams have a stable state a and a stable state b; when the middle part of the curved beam 400 receives a larger external force F and the curved beam 400 changes from the steady state 1 to the intermediate state 2 in the bending process from the steady state 1 to the other steady state 3, the axial direction of the curved beam 400 is compressed first, so that the compression internal energy of the curved beam 400 is continuously increased; as the curved beam 400 continues to buckle, the compressive internal energy of the curved beam 400 begins to gradually decrease as the curved beam 400 changes from intermediate state 2 to another steady state 3. While the ability of the curved beam 400 to elastically deform can be resisted by increasing the stiffness of the curved beam 400, which helps reduce the development of bistable states; the bistable state is mainly reduced by increasing the bending rigidity of the fixed positions of the two ends of the curved beam 400 and the position of the central bending rotating shaft of the curved beam 400. While the state of the shaft penetrating segment 16 before and after destabilization in the related art may be similar to the type of bistable beam in mechanics, based on this, in the embodiment of the present application, any one layer of the conductive layer 117, the base material layer 116 or the cover layer 118 located in the second sub-region 111 in the conductive structure layer 112 is designed, for example, a thinning or hole digging method is used to reduce the rigidity of a part or all of the area of any layer, so as to realize that the rigidity of the first sub-region 110 is greater than the rigidity of the second sub-region 111; or/and, any one layer of the conductive layer 117, the substrate layer 116 or the cover layer 118 located in the first sub-area 110 is designed, for example, the thickness of a part area or all areas of any one layer is increased by adopting a thickening method, so that the rigidity of the first sub-area 110 is higher than that of the second sub-area 111 by using the flexible circuit board. When the number of conductive structure layers 112 in the flexible circuit board is plural, the structure between two adjacent conductive structure layers 112 in the first sub-region 110 may also be designed, for example, adding an additional layer between two adjacent conductive structure layers 112 in the first sub-region 110 to increase the rigidity; alternatively/or in addition, an additional layer is designed between two adjacent conductive structure layers 112 located in the second sub-region 111, but with a smaller thickness than the additional layer on the first sub-region, or holes may be drilled therein to achieve a stiffness of the first sub-region 110 that is greater than the stiffness of the second sub-region 111. The problem of instability of the shaft penetrating section 16 of the flexible circuit board in the related art can be solved by adopting the method. It should be noted that the above modes may be used alone or in combination.

In the description of the present application, a particular feature, structure, material, or characteristic may be combined in any one or more embodiments or examples in a suitable manner.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A flexible circuit board, comprising:

a fixed zone;

the non-fixed area and the fixed area are distributed along the length direction of the flexible circuit board, at least one of two opposite ends of the non-fixed area is connected with the fixed area, and the non-fixed area can be bent and deformed;

2. The flexible circuit board of claim 1, wherein the number of second sub-areas is a plurality and the number of first sub-areas is a plurality;

the plurality of second sub-regions and the plurality of first sub-regions in the non-fixed region are alternately arranged in the length direction of the flexible circuit board, wherein the second sub-region is located between two adjacent first sub-regions.

3. The flexible circuit board of claim 2 wherein the first sub-regions are at opposite ends of the non-anchor region, respectively, the first sub-regions being connected to the anchor region.

4. A flexible circuit board according to any one of claims 1 to 3, wherein the flexible circuit board includes a conductive structure layer and a reinforcing layer which are laminated in a thickness direction of the flexible circuit board;

the reinforcing layer is arranged in the fixed region, and the conductive structure layer covers the fixed region and the non-fixed region.

5. The flexible circuit board of claim 4, wherein the flexible circuit board further comprises a first additional layer, the first additional layer being located in the first sub-region;

at least one of the two opposite sides of the conductive structure layer is provided with the first additional layer.

6. The flexible circuit board of claim 5, wherein the first additional layer is made of foam, polyester resin, fiberglass cloth, or polyimide.

7. The flexible circuit board of claim 4, wherein the conductive structural layer comprises a conductive layer having opposing first and second sides;

8. The flexible circuit board of claim 7, wherein the conductive layer has at least one first recessed groove thereon, the first recessed groove being located in the second sub-region.

9. The flexible circuit board of claim 8, wherein the first concave groove is stepped in a thickness direction of the flexible circuit board.

10. The flexible circuit board of claim 7, wherein the conductive layer comprises at least one first wire; the part of the first lead positioned in the first subarea is a first sub-line, the part of the first lead positioned in the second subarea is a second sub-line, and the first sub-line is electrically connected with the second sub-line;

11. The flexible circuit board of claim 10, wherein a width of the first sub-line is greater than a width of at least a portion of the structure of the second sub-line in a width direction of the flexible circuit board; or/and, the second sub-line is provided with at least one first hole, and the first sub-line is of a solid structure.

12. The flexible circuit board of claim 7, wherein the conductive structure layer further comprises a base material layer, the base material layer and the conductive layer being disposed in a stacked manner in a thickness direction of the flexible circuit board.

13. The flexible circuit board of claim 12, wherein the substrate layer has at least one second recessed groove thereon, the second recessed groove being located in a second sub-region.

14. The flexible circuit board of claim 12 or 13, wherein the conductive structure layer further comprises a cover layer; in the thickness direction of the flexible circuit board, the cover layer, the conductive layer and the base material layer are laminated in order.

15. The flexible circuit board of claim 14, wherein the cover layer has at least one third recessed channel thereon, the third recessed channel being located in the second sub-region.

16. The flexible circuit board of claim 4, wherein the number of conductive structure layers is plural, and a plurality of the conductive structures are stacked in a thickness direction of the flexible circuit board.

17. The flexible circuit board of claim 16, further comprising a second additional layer disposed between adjacent two of the conductive structure layers, the second additional layer being located in the first sub-region.

18. The flexible circuit board of claim 17, further comprising a third additional layer, wherein the third additional layer is further disposed between two adjacent conductive structure layers, and wherein the third additional layer is located in the second sub-region;

the orthographic projection area of the third additional layer in a second plane is smaller than that of the second sub-region in the second plane, and the second plane is parallel to the length direction and the width direction of the flexible circuit board respectively.

19. The flexible circuit board of claim 18, wherein the third additional layer has at least one second hole disposed therein.

20. The flexible circuit board of claim 18, wherein the second additional layer is foam, polyester resin, fiberglass cloth, or polyimide; the third additional layer is made of foam, polyester resin, glass fiber cloth or polyimide.

21. A flexible circuit board according to any of claims 1-3, wherein the cross-section of the first sub-area has a larger area than the cross-section of the second sub-area, the cross-section of the first sub-area being parallel to the thickness direction and the width direction of the flexible circuit board, respectively, and the cross-section of the second sub-area being parallel to the thickness direction and the width direction of the flexible circuit board, respectively.

22. The flexible circuit board of any of claims 1-3, further comprising a number of connection regions, the number of connection regions being two, the number of non-fixed regions being two, the number of fixed regions being three;

23. An electronic device comprising a housing, a spindle mechanism, and a flexible circuit board according to any one of claims 1-22, the housing being rotatably coupled to the spindle mechanism;

the rotating shaft mechanism comprises a base, and the fixed areas at two ends of the flexible circuit board in the length direction are respectively fixedly connected with the base and the shell.