Circuit board and camera module

Abstract

The utility model relates to a circuit board and a camera module, the circuit board comprises a base material layer, a wiring layer and a metal layer, and the base material layer is provided with a first surface and a second surface which deviate from each other; the wiring layer is arranged on the first surface; the metal layer is arranged on the second surface, a stress reducing area is arranged on the metal layer, and the thermal expansion coefficient of the stress reducing area is smaller than that of the metal layer. According to the circuit board provided by the invention, the thermal expansion coefficient of the stress reducing area is smaller than that of the metal layer, so that the thermal stress and thermal expansion deformation degree of the whole metal layer in the temperature change process can be reduced through the stress reducing area; the deformation matching degree of the metal layer and the base material layer during temperature change is guaranteed, so that stress concentration and material damage of the circuit board caused by inconsistent thermal expansion are avoided, and the welding assembly and use requirements of products are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronics, and in particular to a circuit board and a camera module. BACKGROUND

[0002] In the process of manufacturing a printed circuit board (PCB), in order to improve the mechanical stability of the PCB, shield interference, improve heat dissipation performance, or reduce the impedance of the ground wire, a copper plating process is performed on the back surface of the substrate layer (i.e., the surface facing away from the trace layer), thereby forming a full copper layer or other metal layer on the back surface of the substrate layer.

[0003] However, because the substrate layer is usually made of a high polymer material, and the thermal expansion coefficient of the metal (e.g., copper) on the back surface of the substrate layer is different from the thermal expansion coefficient of the substrate layer, when reflow soldering is performed, the different amounts of thermal expansion between the substrate layer and the metal layer will cause thermal stress to be generated, and the uneven distribution of the thermal stress will cause the PCB to warp, which not only affects the appearance quality of the PCB, but also can affect the placement accuracy and soldering reliability of SMT components (surface mount components). SUMMARY

[0004] The present application provides a circuit board and a camera module to solve the technical problem that the difference in thermal expansion coefficients between the substrate layer and the metal layer on the back surface of the substrate layer can easily cause the circuit board to warp and deform.

[0005] In a first aspect, the present application provides a circuit board, comprising:

[0006] a substrate layer, the substrate layer having a first surface and a second surface facing away from each other;

[0007] a trace layer, the trace layer being disposed on the first surface;

[0008] a metal layer, the metal layer being disposed on the second surface, and the metal layer having a stress reduction region disposed thereon, the stress reduction region having a thermal expansion coefficient that is less than the thermal expansion coefficient of the metal layer.

[0009] Optionally, the stress reduction region includes one or more ink regions, and the ink regions are stacked on the side of the metal layer facing away from the substrate layer.

[0010] Optionally, the projection of the stress reduction region on the metal layer is located in the middle of the metal layer.

[0011] Optionally, the circuit board has a recess, and the plurality of ink regions are sequentially arranged along the outer periphery of the recess.

[0012] Optionally, the stress reduction region includes a plurality of ink regions, and the adjacent two ink regions have a predetermined spacing therebetween.

[0013] Optionally, the outer peripheral surface of the ink region includes one or more curved surfaces.

[0014] Optionally, the outer circumferential surface of the ink area further comprises one or more planes, and both ends of each plane are transitionally connected with a curved surface.

[0015] Optionally, the stress relief area comprises a plurality of hollow structures penetrating the metal layer.

[0016] Optionally, the stress relief areas are uniformly distributed on the metal layer.

[0017] In a second aspect, the present application provides a camera module comprising the circuit board provided in the first aspect of the present application.

[0018] Compared with the prior art, the above technical solution provided by the embodiments of the present application has the following advantages:

[0019] The circuit board provided by the embodiments of the present application is provided with a stress relief area on the metal layer on the back of the substrate layer, and since the thermal expansion coefficient of the stress relief area is less than the thermal expansion coefficient of the metal layer, the thermal stress and the thermal expansion deformation degree of the metal layer as a whole during temperature change can be reduced through the stress relief area; the deformation matching degree of the metal layer and the substrate layer when the temperature changes is ensured, thereby avoiding stress concentration and material damage of the circuit board due to inconsistent thermal expansion, and meeting the welding assembly and use requirements of the product.

[0020] The camera module provided by the embodiments of the present application comprises the above circuit board, and the stress relief area of the circuit board can avoid the air welding of the circuit board and other components due to warping deformation, and naturally has the technical effects of the above circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below, and obviously, other drawings can also be obtained by those skilled in the art without creative labor under the premise of not paying the creative labor.

[0023] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings, and these exemplary illustrations do not constitute a limitation on the embodiments, and the elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified, and the drawings do not constitute a proportional limitation.

[0024] Figure 1 The cross section of the circuit board provided by the embodiments of the present application Figure 1 ;

[0025] Figure 2Provided for the embodiments of this application Figure 1 A-direction view Figure 1 ;

[0026] Figure 3 Provided for the embodiments of this application Figure 1 A-direction view Figure 2 ;

[0027] Figure 4 Cross-sectional view of the circuit board provided in the embodiments of this application Figure 2 ;

[0028] Figure 5 Provided for the embodiments of this application Figure 4 View from direction B;

[0029] Figure 6 Cross-sectional view of the circuit board provided in the embodiments of this application Figure 3 ;

[0030] Figure 7 Provided for the embodiments of this application Figure 6 The C-direction view.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Substrate layer; 11. First surface; 12. Second surface;

[0033] 2. Wiring layer;

[0034] 3. Metal layer;

[0035] 4. Stress-reducing zone; 41. Ink zone; 411. First curved surface; 412. Second curved surface; 413. Plane; 42. Hollowed-out structure;

[0036] 5. Depression;

[0037] 6. Solder mask layer. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity, the elements and settings of particular examples in the following description will be described. Of course, they are only examples and are not intended to limit the present application. In addition, reference numerals and / or letters can be repeated in different examples in the present application. Such repetition is for the purpose of simplification and clarity, and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0040] For the purpose of description, spatial relative terms can be used herein to describe the relative position relationship or movement of one element or feature with respect to another element or feature as shown in the drawings, such as "internal", "external", "inner", "outer", "under", "below", "above", "upper", "lower", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over or the posture is changed or the movement state is changed, the directional indications will also change accordingly, for example: the element described as "under" or "below" other elements or features will be oriented as "above" or "above" other elements or features. Therefore, the example term "below" can include both upward and downward positions. The device can be additionally oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used herein are interpreted accordingly.

[0041] To solve the technical problem that the difference in the coefficient of thermal expansion of the substrate layer 1 and the metal layer 3 on the back thereof in the prior art easily causes the circuit board to warp and deform, the present application provides a circuit board and a camera module, which is provided with a stress reduction area 4 on the metal layer 3 on the back of the substrate layer 1. Since the coefficient of thermal expansion of the stress reduction area 4 is smaller than that of the metal layer 3, the thermal stress of the stress reduction area 4 is smaller than that of other areas of the metal layer 3, thereby reducing the overall coefficient of thermal expansion of the metal layer 3, limiting the expansion deformation amount of the metal layer 3, reducing the overall size change of the metal layer 3 due to thermal expansion when the temperature changes, and ensuring the deformation matching degree of the metal layer 3 and the substrate layer 1 when the temperature changes, thereby avoiding stress concentration and material damage of the circuit board due to inconsistent thermal expansion, and meeting the welding assembly and use requirements of the product.

[0042] Please refer to Figures 1 to 7 The first aspect of the embodiments of the present application provides a circuit board, which comprises a substrate layer 1, a wiring layer 2 and a metal layer 3. The substrate layer 1 has a first surface 11 and a second surface 12 facing away from each other, which are respectively used to connect with the wiring layer 2 and the metal layer 3, as shown in Figure 1 .

[0043] Please refer to Figure 1 , Figure 4 and Figure 6 , the wiring layer 2 is arranged on the first surface 11, which is the front surface of the substrate layer 1, and can connect multiple electrical elements on the front surface of the circuit board together to form a complete circuit path, so that the current and signals can be smoothly transmitted in the circuit board. The wiring layer 2 can be made of copper foil, aluminum foil or silver foil, etc. after etching; since copper foil has good electrical conductivity and relatively low price, it is preferred to use copper foil as the material for preparing the wiring layer 2.

[0044] It should be noted that a solder mask layer 6 is also arranged above the wiring layer 2, which can only expose the pads in the wiring layer 2, and provide insulation protection for the wiring layer 2 through the solder mask layer 6 to prevent short circuit outside the circuit board and ensure the normal operation of the circuit.

[0045] Please refer to Figure 1 , Figure 4 and Figure 6 , the metal layer 3 is arranged on the second surface 12, which is the back surface of the substrate layer 1, and since the metal material has high strength and toughness, arranging it on the back surface of the substrate layer 1 can enhance the strength of the entire structure. At the same time, the metal layer 3 can also be used as a ground layer to provide a stable potential reference point for the circuit board, which helps to reduce noise and interference.

[0046] The metal layer 3 is provided with a stress reduction area 4, and the thermal expansion coefficient of the stress reduction area 4 is less than that of the metal layer 3. The stress reduction area 4 can reduce the thermal stress and thermal expansion deformation degree of the metal layer 3 as a whole during temperature changes (such as during reflow soldering operation); it can ensure the deformation matching degree of the metal layer 3 and the substrate layer 1 when the temperature changes, thereby avoiding stress concentration and material damage of the circuit board due to inconsistent thermal expansion, and meeting the welding assembly and use requirements of the product.

[0047] It should be noted that the stress reduction area 4 can reduce the thermal stress of the area on the metal layer 3 corresponding to the position of the stress reduction area 4, and the stress reduction area 4 can be formed by coating or pasting a material with a small thermal expansion coefficient on the metal layer 3 or setting a hollow area on the metal layer 3.

[0048] When the stress reduction area 4 is formed by coating or pasting a material with a small thermal expansion coefficient on the metal layer 3, since the material with a small thermal expansion coefficient expands less when heated, when the stress reduction area 4 formed by such material is arranged on the metal layer 3, it can form a certain "thermal expansion and cold contraction" compensation mechanism with the metal layer 3, which helps to reduce the deformation of the metal layer 3 due to thermal expansion, because the stress reduction area 4 will produce a certain constraint effect on the metal layer 3 when it expands, thereby limiting the deformation range of the metal layer 3, as shown in Figures 1 to 5 .

[0049] When the stress relief zone 4 is formed by setting the hollowed-out area on the metal layer 3, the stress relief zone 4 does not have metal material that can expand, and the thermal expansion coefficient of the stress relief zone 4 is considered to be zero, which is equivalent to introducing a relief area in the metal layer 3. These relief areas can provide additional deformation space when other metal materials of the metal layer 3 are thermally expanded, thereby dispersing and relieving the stress concentration of the metal layer 3 caused by thermal expansion. At the same time, the hollowed-out area can also act as a heat dissipation channel to accelerate the cooling process of the metal layer 3, further reducing the risk of thermal expansion deformation, as shown in Figures 6 to 7 .

[0050] In some embodiments of the present application, the metal layer 3 and the wiring layer 2 can be made of the same material, preferably copper material, which can improve the manufacturing efficiency of the circuit board. Since copper has high thermal conductivity, it can effectively conduct heat from the heating element to the surrounding environment. The wiring layer 2 on the front side of the substrate layer 1 can act as a heat conduction path to help disperse and dissipate the heat generated by the element. At the same time, the copper metal layer 3 on the back side of the substrate layer 1 can also act as a heat dissipation layer to further enhance the thermal management effect of the circuit board, which is crucial for improving the reliability and prolonging the service life of the circuit board.

[0051] In some embodiments of the present application, please refer to Figures 1 to 5 , the stress relief zone 4 includes one or more ink areas 41, which are stacked on the side of the metal layer 3 away from the substrate layer 1. Since the thermal expansion coefficient of the ink material is less than that of the metal material (such as copper) in the metal layer 3, the cured ink area 41 can form a thermal expansion and contraction compensation mechanism for the metal layer 3. By restricting the deformation range of the metal layer 3 through the ink area 41 when the metal layer 3 expands, the warping deformation of the circuit board is reduced.

[0052] It should be noted that according to the thermal stress distribution and thermal expansion deformation characteristics of the metal layer 3, the solder resist ink is applied to part of the metal layer 3, and the cured solder resist ink forms one or more stress relief zones 4 with a certain thickness on the back of the metal layer 3. The area without solder resist ink (i.e. the area without ink area 41) is a bare copper area. By limiting the thermal expansion deformation of part of the metal layer 3 through one or more ink areas 41, the expansion deformation of the entire metal layer 3 is matched with the expansion deformation of the substrate layer 1, and the empty soldering of the components caused by the warping deformation of the circuit board during reflow soldering is reduced.

[0053] When the metal layer 3 on the back side of the substrate layer 1 is a full copper layer, if the temperature control of the high-temperature processing process (such as reflow soldering, wave soldering, etc.) is not proper or the heating rate is too fast, it will intensify the internal stress of the material, leading to deformation. The central region of the metal layer 3 may produce greater deformation due to more uniform or more intense heating, thereby causing the middle part of the circuit board to warp upwards.

[0054] To solve the above problems, in some embodiments of the present application, referring to Figures 1 to 3 , the projection of the stress-reducing area 4 on the metal layer 3 is located in the middle of the metal layer 3, which can limit the deformation of the central region of the metal layer 3, thereby reducing the deformation stress (i.e. thermal stress) and the degree of deformation of the central region of the metal layer 3 and the circuit board.

[0055] When the metal layer 3 on the back of the substrate layer 1 is provided with a recess or a through groove, the metal material around the recess or the through groove tends to have the characteristic of large middle deformation and small edge deformation (the edge includes the edge close to the outer side of the metal layer 3 and the edge close to the area of the recess or the through groove), which is easy to cause uneven deformation of the circuit board and affect the welding of components.

[0056] To solve the above problems, in some embodiments of the present application, referring to Figures 4 to 5 , the circuit board is provided with a recess 5 to facilitate the assembly of devices on the circuit board, and a plurality of ink areas 41 are sequentially arranged on the metal layer 3 along the outer periphery of the recess 5, which can avoid the problem of large middle deformation and small edge deformation of the metal material around the recess 5, make the deformation degree of the metal material around the recess 5 consistent, and match the deformation degree of the substrate layer 1, thereby avoiding the warping deformation of the circuit board around the recess 5.

[0057] In some embodiments of the present application, referring to Figures 1 to 5 , the stress-reducing area 4 includes a plurality of ink areas 41, and the adjacent two ink areas 41 have a preset interval, which can avoid the stress concentration inside the ink area 41 due to the large area of the single ink area 41, and the preset gap between the adjacent ink areas 41 provides a deformation space for the ink area 41, which can provide additional deformation space when the ink area 41 is heated and expanded, thereby dispersing and relieving the stress concentration of the stress-reducing area 4 itself caused by thermal expansion.

[0058] In some embodiments of the present application, when the stress-reducing area 4 is concentrated in the central region of the metal layer 3, the preset interval between the adjacent two ink areas 41 is as shown in Figure 2 L1 and Figure 3 L2, which is the net distance (i.e. the distance between the outermost edges) between the adjacent two ink areas 41.

[0059] In some other embodiments of the present application, when the central region of the metal layer 3 is provided with a recess 5, and a plurality of ink areas 41 are distributed around the outer periphery of the recess 5, the interval between the adjacent two ink areas 41 is as shown in Figure 5 L3 and L4, which can keep the appropriate lateral or longitudinal spacing between the adjacent two ink areas 41.

[0060] It should be noted that the preset interval can be set according to the thermal stress distribution, heat dissipation requirement and material characteristics of the stress relief area 4, as long as the thermal stress of the metal layer 3 can be effectively relieved, and the purpose of the present application can be achieved.

[0061] In some embodiments of the present application, the preset interval is greater than or equal to 0.8 mm, and preferably 1 mm. The preset interval can form a reserved deformation space between the adjacent two ink areas 41, and can reduce the manufacturing difficulty of preparing two or more adjacent ink areas 41 by coating solder resist ink.

[0062] In some embodiments of the present application, referring to Figure 2 , Figure 3 and Figure 5 , the outer peripheral surface of the ink area 41 includes one or more curved surfaces. The outer peripheral surface of the ink area 41 can avoid the existence of sharp edges, and can avoid the stress concentration on the outer peripheral surface of the ink area 41, thereby affecting the thermal stress relieving effect of the ink area 41 on the metal layer 3.

[0063] It should be noted that the outer peripheral surface of the ink area 41 can be a cylindrical surface (such as the first curved surface 411 in Figure 2 ) or other curved surfaces (such as the second curved surface 412 in Figure 3 ). The cross section of the ink area 41 is in a symmetrical shape such as a circle or an ellipse, so as to ensure the uniform distribution of thermal stress.

[0064] In some embodiments of the present application, referring to Figure 3 , the outer peripheral surface of the ink area 41 further includes one or more flat surfaces 413, and both ends of the flat surface 413 are transitionally connected with curved surfaces (i.e. the second curved surface 412). The cross section of the ink area 41 can be a polygonal structure (such as a rectangle, a square, a triangle, etc.) with rounded corners. The polygonal structure is preferably a regular polygon, and the corners of the polygonal structure are smoothly transitioned by the second curved surface 412, so as to avoid the stress concentration on the outer peripheral surface of the ink area 41.

[0065] It should be noted that the cross-sectional size of each ink area 41 can be set according to the thermal stress distribution, heat dissipation requirement and material characteristics of the stress relief area 4, as long as the thermal stress of the metal layer 3 can be effectively relieved, and the purpose of the present application can be achieved.

[0066] In some embodiments of the present application, the cross-sectional size of the ink area 41 is 0.6-1.5 mm. Specifically, when the cross-sectional shape of the ink area 41 is a circle, if the ink area 41 is arranged in the central region of the metal layer 3, the diameter of the cross-sectional shape is preferably 1-1.2 mm; if the ink area 41 is arranged on the outer periphery of the recess 5, the diameter of the cross-sectional shape is preferably 0.6-1.2 mm; when the cross-sectional shape of the ink area 41 is a rectangle, the side length of the ink area 41 is preferably 1.2-1.5 mm.

[0067] In some embodiments of the present application, please refer to Figures 6 to 7 , the stress relief area 4 includes a plurality of hollow structures 42 arranged on the metal layer 3, which are used to form a plurality of hollow areas on the metal layer 3, and the hollow areas can provide additional deformation space when other metal materials of the metal layer 3 expand due to heat, thereby dispersing and relieving the stress concentration of the metal layer 3 caused by thermal expansion.

[0068] In some embodiments of the present application, please refer to Figure 2 , Figure 3 , Figure 5 and Figure 7 , the stress relief area 4 is uniformly distributed on the metal layer 3, and the uniformly distributed stress relief area 4 can effectively disperse and relieve the stress concentration in the metal layer 3. When the metal layer 3 is subjected to external load or temperature change, the stress will no longer be limited to a local area, but can be more evenly distributed on the entire metal layer 3, which can relieve the warping deformation of the metal layer 3 and the circuit board during soldering assembly.

[0069] In some embodiments of the present application, please refer to Figure 2 and Figure 3 , the plurality of ink areas 41 are uniformly arranged in the central area of the metal layer 3, which can uniformly disperse the thermal stress of the central area of the metal layer 3, and avoid the central part of the metal layer 3 from being raised upward due to thermal expansion during heating.

[0070] In some embodiments of the present application, please refer to Figure 5 , the plurality of ink areas 41 are uniformly distributed on the outer periphery of the recess 5, which can uniformly disperse the stress of the metal layer 3 material on the outer periphery of the recess 5, and avoid the metal plate body on the outer periphery of the recess 5 from being unevenly deformed (i.e., the central plate body is deformed greatly and the two side edges are deformed slightly).

[0071] In some embodiments of the present application, the plurality of hollow structures 42 are uniformly arranged on the metal layer 3, so that the metal layer 3 is in the form of a grid copper plate, which can uniformly disperse the thermal stress generated on the metal layer 3 due to heating, change the entire copper surface on the back of the substrate layer 1 to a grid copper, improve the flatness of the circuit board plane 413, reduce thermal stress, and thus improve the deformation of the PCB.

[0072] It should be noted that when the stress relief area 4 is arranged on the metal layer 3, the via (VIA) on the circuit board should be avoided, so as to reduce the deformation of the circuit board while avoiding the influence of the arrangement of the stress relief area 4 on the assembly and normal use of the circuit board.

[0073] Please refer to Figures 1 to 7The second aspect of the embodiments of the present application provides a camera module including the circuit board described in the above embodiments. Due to the presence of the stress reduction area 4, the warping deformation generated in the process of processing the circuit board can be reduced, which is beneficial to realize the welding assembly of the components on the circuit board. The master control chip, the image sensor, the lens and other key components can be efficiently and reliably connected by using the circuit board. The signals between these components can be efficiently transmitted through the circuit board, so as to ensure that the camera module can work normally.

[0074] In some embodiments of the present application, the circuit board can be a radio frequency printed circuit board (RF PCB) capable of processing high-speed radio frequency signals, thereby meeting the requirements of high-speed data transmission and signal processing in the camera module and providing stable signal support for high-quality image and video transmission.

[0075] It should be understood that the terms used herein are for the purpose of describing particular example embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically indicated as such. It is also to be understood that additional or alternative steps can be employed.

[0076] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, the terms such as "first", "second" and other numerical terms when used herein do not imply a sequence or an order. Therefore, a first element, component, region, layer or section discussed below can be referred to as a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0077] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A circuit board, characterized in that, include: A substrate layer (1) having a first surface (11) and a second surface (12) that are opposite to each other; A wiring layer (2) is disposed on the first surface (11); A metal layer (3) is disposed on the second surface (12), and a stress-reducing region (4) is disposed on the metal layer (3), wherein the coefficient of thermal expansion of the stress-reducing region (4) is less than the coefficient of thermal expansion of the metal layer (3).

2. The circuit board according to claim 1, characterized in that, The stress-reducing zone (4) includes one or more ink zones (41), which are stacked on the side of the metal layer (3) away from the substrate layer (1).

3. The circuit board according to claim 2, characterized in that, The projection of the stress-reducing zone (4) onto the metal layer (3) is located in the middle of the metal layer (3).

4. The circuit board according to claim 2, characterized in that, The circuit board has a recessed portion (5), and a plurality of ink areas (41) are arranged sequentially along the outer periphery of the recessed portion (5).

5. The circuit board according to any one of claims 2 to 4, characterized in that, The stress-reducing zone (4) includes a plurality of ink zones (41), and there is a preset distance between two adjacent ink zones (41).

6. The circuit board according to any one of claims 2 to 4, characterized in that, The outer peripheral surface of the ink area (41) includes one or more curved surfaces.

7. The circuit board according to claim 6, characterized in that, The outer peripheral surface of the ink area (41) also includes one or more planes (413), both ends of which are transitionally connected to the curved surface.

8. The circuit board according to claim 1, characterized in that, The stress-reducing zone (4) includes multiple perforated structures (42) extending through the metal layer (3).

9. The circuit board according to claim 1, characterized in that, The stress-reducing zone (4) is uniformly distributed on the metal layer (3).

10. A camera module, characterized in that, Includes the circuit board as described in any one of claims 1 to 9.

Images