Circuit board and electronic device

Abstract

The application discloses a circuit board and an electronic device, and belongs to the technical field of electronic products. The circuit board comprises a conductive substrate, a temperature-sensitive element formed by a thermosensitive material and embedded in the inside of the conductive substrate, and the equivalent resistance value of the temperature-sensitive element changes with temperature; and at least two detection electrodes electrically connected with the temperature-sensitive element and used for outputting the equivalent resistance value of the temperature-sensitive element to an external circuit.

Description

Technical Field

[0001] This application belongs to the field of electronic product technology, specifically relating to a circuit board and an electronic device. Background Technology

[0002] Electronic devices are currently developing towards miniaturization and high integration, and the available internal space is continuously being compressed. However, with the increase in functional modules, the number of critical heat-generating areas that require temperature monitoring is also increasing.

[0003] In related technologies, it is common to use negative temperature coefficient (NTC) thermistors mounted on the surface of flexible printed circuits (FPCs) to achieve real-time temperature detection of heat-generating areas. For example, NTCs are soldered onto the FPC of a flash lamp for over-temperature protection of LED chips and driver ICs; NTCs are mounted on the main FPC for temperature monitoring of the coil and battery during wireless charging.

[0004] However, NTC devices and their pads directly encroach on the surface space of the FPC, and due to layout space limitations, NTCs are often far from heat sources, making timely and accurate temperature monitoring impossible. This deficiency is particularly prominent in camera module applications. With the popularization of high-pixel, high-frame-rate recording technology, camera modules have become a new critical heat-generating area. However, due to their extremely limited internal space, traditional surface-mount NTCs cannot be installed. Currently, temperature can only be estimated by software or indirectly measured, making it difficult to achieve accurate and reliable over-temperature protection.

[0005] Therefore, given the limited space on the circuit board surface, how to achieve a temperature monitoring solution that occupies little space and has high detection accuracy is an urgent technical problem to be solved. Summary of the Invention

[0006] The purpose of this application is to provide a circuit board and electronic device to solve the problem of how to achieve a temperature monitoring solution with small space occupation and high detection accuracy when the surface space of the circuit board is limited.

[0007] To solve the above-mentioned technical problems, this application is implemented as follows:

[0008] In a first aspect, embodiments of this application provide a circuit board, including:

[0009] Conductive substrate;

[0010] A temperature-sensitive element, formed of a thermistor material, is embedded inside the conductive substrate, and the equivalent resistance of the temperature-sensitive element changes with temperature.

[0011] At least two detection electrodes are electrically connected to the temperature-sensitive element and are used to output the equivalent resistance value of the temperature-sensitive element to an external circuit.

[0012] Secondly, embodiments of this application provide an electronic device, including a circuit board as described in the first aspect; and a heating element, wherein a temperature-sensitive element in the circuit board is used to detect the heat generated by the heating element.

[0013] In this embodiment, the temperature-sensitive element and at least two detection electrodes are electrically connected to form an embedded resistor. The embedded resistor and the external circuit form a voltage divider detection circuit, which can detect the equivalent resistance value of the temperature-sensitive element in real time. By embedding the embedded resistor in the conductive substrate, it does not occupy the surface space of the circuit board, making it suitable for applications where the surface space of the circuit board is limited. Furthermore, it allows the embedded resistor to be placed closer to the heat-generating element, shortening the heat conduction path between the embedded resistor and the heat source, reducing thermal hysteresis, and improving temperature detection accuracy. Attached Figure Description

[0014] Figure 1 One of the schematic diagrams of the circuit board structure according to an embodiment of the present invention;

[0015] Figure 2 This describes an embodiment of the present invention. Figure 1 Front view of the embedded resistor R;

[0016] Figure 3 A second schematic diagram illustrating the structure of a circuit board according to an embodiment of the present invention;

[0017] Figure 4 The third schematic diagram illustrating the structure of the circuit board according to an embodiment of the present invention;

[0018] Figure 5 A schematic diagram showing the structure of an electronic device;

[0019] Figure 6 express Figure 5 A magnified view of a portion of point D in the middle;

[0020] Figure 7 express Figure 5 A magnified view of a portion of point E in the middle;

[0021] Figure 8 This is a schematic diagram showing the structure of the camera module according to an embodiment of the present invention;

[0022] Figure 9 A schematic diagram illustrating the mounting structure of the flash and circuit board according to an embodiment of the present invention;

[0023] Figure 10 This diagram illustrates the mounting structure of the flash and circuit board in the prior art.

[0024] Figure 11 A schematic diagram illustrating the mounting structure of the battery and circuit board according to an embodiment of the present invention;

[0025] Figure 12 This diagram illustrates the existing battery and circuit board mounting structure.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100 - Conductive substrate; 110 - Base insulating layer; S1 - Through hole; V - Cavity; C1 - First channel; C2 - Second channel; 120 - Conductive layer; 121 - First conductive layer; 122 - Second conductive layer; 200 - Temperature sensing element; 300 - Detection electrode; 310 - First detection electrode; 320 - Second detection electrode; 400 - First insulating cover layer; 500 - Second insulating cover layer; 600 - First adhesive layer; 700 - Second adhesive layer; 810-Camera module; 811-Lens; 812-Motor; 813-Filter; 814-Image sensor; 815-Reinforcing steel sheet; 816-Base; 817-Connector; 818-Rigid-flex circuit board; 820-Flash; 821-Foam; 830-Battery; 840-Charging coil; 910-Middle frame; 920-Main board; 930-Sub-board; 940-Nickel-gold layer or Organic solderability preservative (OSP); 950-Bracket; R-Embedded resistor; F-Conductive material. Detailed Implementation

[0028] 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.

[0029] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0030] The control method provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0031] Please refer to Figures 1 to 4 This invention provides a circuit board including a conductive substrate 100, a temperature-sensitive element 200, and at least two detection electrodes 300. The temperature-sensitive element 200 is formed of a thermistor material and is embedded inside the conductive substrate 100. The equivalent resistance of the temperature-sensitive element 200 changes with temperature. The at least two detection electrodes 300 are electrically connected to the temperature-sensitive element 200 and are used to output the equivalent resistance value of the temperature-sensitive element 200 to an external circuit.

[0032] In this embodiment, the temperature-sensitive element 200 and at least two detection electrodes 300 are electrically connected to form an embedded resistor R. The embedded resistor R and the external circuit form a voltage divider detection circuit, which can detect the equivalent resistance value of the temperature-sensitive element 200 in real time. By embedding the embedded resistor R within the conductive substrate 100, it does not occupy the surface space of the circuit board, making it suitable for applications where the surface space of the circuit board is limited. Furthermore, it allows the embedded resistor R to be placed closer to the heat-generating element, shortening the heat conduction path between the embedded resistor and the heat source, reducing thermal hysteresis, and improving temperature detection accuracy.

[0033] Furthermore, since the circuit board in this application does not require mounting NTC thermistors, the mounting process is simplified, avoiding the risk of cracking of NTC thermistors during transportation, assembly, and drops. The embedded resistors are integrated with the circuit board, eliminating potential issues such as solder joint misalignment and cold solder joints. Moreover, the application of embedded resistors can significantly reduce the thickness of the temperature sensing unit, eliminating the need for pre-reserved slots and stacking space inside electronic devices, thus contributing to the thinner and lighter design of electronic devices. Even further, utilizing the flexible and bendable characteristics of FPCs, embedded resistors can be attached to heating elements, achieving a flexible three-dimensional layout, overcoming the limitations of planar mounting, and enabling temperature detection in densely packed heating areas, suitable for thermal management scenarios of highly integrated devices.

[0034] In some embodiments of this application, the conductive substrate 100 includes a substrate insulating layer 110 and a conductive layer 120. The conductive layer 120 includes a first conductive layer 121 and a second conductive layer 122, which are respectively formed on two opposing surfaces of the substrate insulating layer 110.

[0035] Optionally, the substrate insulating layer 110 is a polyimide (PI) layer of a flexible copper clad laminate (FCCL), and the conductive layer 120 is a copper layer of FCCL deposited on at least one side of the FCCL PI layer. For example, taking a circuit board as an adhesive-free double-sided flexible copper clad laminate, the conductive substrate 100 may include: an FCCL PI layer, a first copper foil layer deposited on the upper surface of the FCCL PI layer, a second copper foil layer deposited on the lower surface of the FCCL PI layer; and at least one metallized via perpendicularly penetrating the FCCL PI layer, the wall of the metallized via being plated with copper, and the first copper foil layer and the second copper foil layer being electrically connected through a copper plating layer; or a blind via perpendicularly penetrating the FCCL PI layer, the blind via being plated with copper, and the first copper foil layer being electrically connected to the second copper foil layer through the copper plating inside the blind via.

[0036] In some embodiments of this application, the circuit board further includes:

[0037] The first insulating cover layer 400 is located on the first side of the conductive substrate 100;

[0038] The second insulating cover layer 500 is located on the second side of the conductive substrate 100;

[0039] The first adhesive layer 600 is sandwiched between the first insulating cover layer 400 and the first side of the conductive substrate 100.

[0040] The second adhesive layer 700 is sandwiched between the second insulating cover layer 500 and the second side of the conductive substrate 100.

[0041] For example, see Figure 1 , Figures 3 to 4 The circuit board includes a first insulating cover layer 400, a first adhesive layer 600, a conductive substrate 100, a second adhesive layer 700, and a second insulating cover layer 500 stacked sequentially from top to bottom. The first insulating cover layer 400 and the second insulating cover layer 500 are located on the outermost side of the circuit board, and the base insulating layer and conductive layer located in the middle are completely wrapped by the upper and lower cover insulating layers through the adhesive layer.

[0042] Optionally, the first insulating cover layer 400 and the second insulating cover layer 500 are both coverlay (CVL) PI layers, and the first adhesive layer 600 and the second adhesive layer 700 are CVL adhesive layers.

[0043] It should be understood that the above embodiments are merely examples of optional implementations of the present invention and are not intended to limit the present invention. Those skilled in the art, within the scope of the present invention's concept, can make various obvious modifications, equivalent substitutions, combinations, or variations to the technical solutions described in the above embodiments, and these modifications, substitutions, combinations, or variations should all be included within the protection scope of the present invention. Specifically, the circuit board structure of this application is not limited to the materials disclosed in the above embodiments. For example, the substrate insulating layer 110 can be made of other flexible and insulating polymer material layers besides the polyimide layer of flexible copper-clad laminate; the conductive layer 120 can be made of other conductive metal layers or other conductive composite material layers besides the copper foil layer of FCCL; the first insulating cover layer 400 and the second insulating cover layer 500 can be made of other flexible material layers with insulating and protective functions besides the polyimide layer of the cover film; the first adhesive layer 600 and the second adhesive layer 700 can be made of other adhesive material layers besides the CVL adhesive layer.

[0044] Furthermore, the circuit board of this application is not limited to the double-sided flexible copper-clad laminate disclosed in the above embodiments. For example, a single-sided covering structure can also be adopted, that is, an insulating covering layer and an adhesive layer are only provided on one side of the conductive substrate 100; or a structure with three or more conductive layers 120 and two or more base insulating layers 110 can be provided; for application scenarios that require both rigidity and flexibility, a rigid-flex board structure can also be adopted, that is, a composite structure in which part of the area is a rigid circuit board and part of the area is a flexible circuit board.

[0045] In some embodiments of this application, see Figures 1 to 2 The temperature-sensitive element 200 is disposed between the first conductive layer 121 and the substrate insulating layer 110; at least two detection electrodes 300 include a first detection electrode 310 and a second detection electrode 320; the first detection electrode 310 is formed by a first portion of the first conductive layer 121 and is electrically connected to a first end of the temperature-sensitive element 200; the second detection electrode 320 is formed by a second portion of the first conductive layer 121 and is electrically connected to a second end of the temperature-sensitive element 200; wherein the first portion and the second portion of the first conductive layer 121 are mutually insulated.

[0046] For example, NTC resistive material can be deposited between the copper layer and the PI layer of FCCL by sputtering or electroplating to form a buried thin-film resistor. Heat treatment then stabilizes the resistive material's performance. The NTC resistive material is a semiconductor ceramic material whose resistivity decreases with increasing temperature, and its composition can be Ni-P resistive material or materials with negative resistance characteristics (such as metal oxides like manganese / cobalt / nickel / copper / tungsten).

[0047] In practical implementation, it is recommended that the horizontal position of the embedded resistor R be close to the center of the battery for more accurate temperature detection; a magnified and 3D schematic diagram of the embedded resistor stack design is shown below. Figure 2 As shown, the embedded resistor R is located above the FCCL PI layer and is wrapped by the CVL adhesive layer. The two copper electrodes serve as two detection electrodes 300 and together with the NTC thermistor material, they constitute the embedded resistor.

[0048] The resistance of the embedded resistor film is:

[0049] (1);

[0050] In equation (1), R ρ is the resistance of the embedded resistor (in Ω); L is the resistivity of the material (in Ω·cm); L is the distance between the two copper electrodes (in Wiecm); W is the width of the resistor (in cm); t is the thickness of the resistor (in cm).

[0051] When L and W are the same, the resistance value of the embedded resistor The calculation is based on the number of sheet resistors, i.e.:

[0052] (2);

[0053] In equation (2), R W Here, N represents the resistance value of the sheet resistor (in Ω / sheet), and N is the number of sheet resistors. Therefore, the resistance value of the embedded resistor R is... It is related to the number of embedded resistors R, the film thickness, and the properties of the film material.

[0054] In some embodiments of this application, a through-hole S1 is formed on the substrate insulating layer 110, and a temperature-sensitive element 200 is formed by filling the through-hole S1 with a thermosensitive material; at least two detection electrodes 300 include a first detection electrode 310 and a second detection electrode 320; the first detection electrode 310 is formed by a portion of the first conductive layer 121 and is electrically connected to the first end of the temperature-sensitive element 200; the second detection electrode 320 is formed by a portion of the second conductive layer 122 and is electrically connected to the second end of the temperature-sensitive element 200.

[0055] For example, see Figure 3 NTC thermistor material can be introduced by drilling holes in the FCCL PI layer to form a buried resistor with the upper and lower copper layers. The NTC thermistor material can be introduced into the through-hole S1 by printing plugs, and then the upper copper electrode is electroplated to fill the hole, thus obtaining the buried resistor structure. To prevent short circuits, copper-plated blind vias are prohibited in other locations between the upper and lower copper layers.

[0056] In some embodiments of this application, a cavity V is formed inside the substrate insulating layer 110, and a first channel C1 and a second channel C2 are formed in the thickness portion between the cavity V and the surface of the substrate insulating layer 110; the temperature sensing element 200 is disposed inside the cavity V; at least two detection electrodes 300 include a first detection electrode 310 and a second detection electrode 320; the first detection electrode 310 is formed by a first conductive region in the conductive layer 120 and is electrically connected to a first end of the temperature sensing element 200 through the first channel C1; the second detection electrode 320 is formed by a second conductive region in the conductive layer 120 and is electrically connected to a first end of the temperature sensing element 200 through the second channel C2.

[0057] For example, see Figure 4 Both the first conductive region and the second conductive region are formed on the first conductive layer 121. The first detection electrode 310 is located in the first conductive region, and the second detection electrode 320 is located in the second conductive region. The first conductive region and the second conductive region are insulated from each other.

[0058] For example, a first conductive region is formed on a first conductive layer 121, and a second conductive region is formed on a second conductive layer 122. A first detection electrode 310 is located in the first conductive region, and a second detection electrode 320 is located in the second conductive region. That is, the first detection electrode 310 and the second detection electrode 320 are located on opposite sides of the substrate insulating layer 110.

[0059] In some embodiments of this application, the cavity V includes a first space, a second space, and a third space, with the second space sandwiched between the first space and the third space; the temperature-sensitive element 200 is disposed in the second space, and the first space, the third space, the first channel C1, and the second channel C2 are filled with conductive material F; the conductive layer 120 is electrically connected to the temperature-sensitive element 200 through the conductive material F.

[0060] See Figure 4 The schematic cross-section of the circuit board shown shows that the first space, the second space and the third space in the cavity V are arranged side by side along the extension direction of the substrate insulating layer 110. The temperature sensitive element 200 is located in the second space and sandwiched between the conductive material F in the first space and the conductive material F in the third space.

[0061] For example, the FPC using a double-layer blind via process can introduce a dummy copper foil and an NTC thin-film resistor inside the FCCL PI layer. The dummy copper foil can be introduced into the cavity V, the first channel C1, and the second channel C2 by electroplating or sputtering. The NTC thin-film resistor can be introduced into the cavity V by electroplating, sputtering, and printing. The FCCL PI layer can be pressed together by hot pressing or adhesive bonding. The NTC thermistor buried resistor consists of copper electrodes formed by the dummy copper foil in the two conductive regions, which serve as two detection electrodes 300. The two copper electrodes are electrically connected to the NTC thermistor thin-film material to form the buried resistor R. The buried resistor R is connected to the surface circuitry through a blind via. Figure 4 The first channel C1 and the second channel C2 are blind holes.

[0062] This application also provides an electronic device, including a circuit board as described above; and a heating element, wherein a temperature-sensitive element 200 in the circuit board is used to detect the heat generated by the heating element.

[0063] In this implementation, the temperature-sensitive element 200 is embedded inside the conductive substrate 100. The temperature-sensitive element 200 and at least two detection electrodes 300 are electrically connected to form an embedded resistor R. The embedded resistor R and the external circuit form a voltage divider detection circuit, which can detect the equivalent resistance value of the temperature-sensitive element 200 in real time. By embedding the embedded resistor R inside the conductive substrate 100, it does not occupy the surface space of the circuit board, making it suitable for applications where the surface space of the circuit board is limited. Furthermore, it allows the embedded resistor R to be placed closer to the heat-generating element, improving detection accuracy.

[0064] See Figure 5 and Figure 8 In some embodiments of this application, the heating element includes the image sensor 814 of the camera module 810 or a driver integrated circuit.

[0065] In practice, the camera module 810 is mounted on the motherboard 920 and is used to acquire external image information and convert it into electrical signals for output to the motherboard 920 for processing. For example... Figure 8As shown, the camera module 810 includes a lens 811, a motor 812, a filter 813, an image sensor 814, a reinforcing steel sheet 815, a base 816, a connector 817, and a rigid-flex circuit board 818. The lens 811 is an optical imaging lens used to converge incident visible light to the image sensor 814 below. The motor 812 is annular and sleeve-shaped, fitted around the outer periphery of the lens 811, with its inner wall engaging with the outer wall of the lens 811. In this embodiment, the motor 812 is preferably a voice coil motor, used to drive the lens 811 to reciprocate along the optical axis, thereby achieving the autofocus function of the camera module. The base 816 is located below the motor 812, with its upper surface fixedly connected to the lower surface of the motor 812. A through-cavity is formed in the center of the base 816, and a filter 813 is fixedly installed within this cavity, positioned directly below the light-emitting surface of the lens 811. The filter 813 filters infrared light from the incident light. An image sensor 814 is positioned directly below the filter 813, with its photosensitive surface facing upwards and directly opposite the filter 813. It receives the light converged by the lens 811 and filtered by the filter 813, and converts the optical signal into an electrical signal. The image sensor 814 is soldered to the upper surface of a rigid-flex circuit board 818 using a surface mount process, forming a reliable electrical and mechanical connection with the rigid-flex circuit board 818.

[0066] The rigid-flex circuit board 818 comprises an integrally formed rigid portion and a flexible portion. The rigid portion is located directly below the base 816, and the image sensor 814 is mounted on its upper surface. The lower end face of the base 816 is bonded and fixed to the upper surface of the rigid portion of the rigid-flex circuit board 818. The flexible portion extends horizontally outward from one side of the rigid portion and can be bent to adapt to the internal spatial layout of the electronic device. A connector 817 is provided at the end of the flexible portion, which is used to connect and cooperate with the motherboard 920 of the electronic device to realize electrical signal transmission between the camera module 810 and the motherboard 920. A reinforcing steel sheet 815 is attached to the lower surface of the rigid portion of the rigid-flex circuit board 818 to enhance the structural strength of the rigid portion and ensure the flatness of the image sensor 814 during installation.

[0067] In this embodiment, a buried resistor is provided at point T in the flexible portion of the rigid-flex circuit board 818. A partial magnified view of point T can be seen as follows: Figure 1 , Figures 3 to 4 One of the structural forms in the design. The flexible part can be used to extend and bend the embedded resistor R and attach it to the vicinity of the camera module 810, providing flexible arrangement capabilities in three-dimensional space, which can significantly improve temperature measurement accuracy and response speed.

[0068] Of course, a resistor can also be embedded in the rigid part of the rigid-flex circuit board 818 to get closer to the core heat-generating sensing IC area and achieve more accurate temperature detection.

[0069] In some embodiments of this application, the heating element is the light-emitting element of the flash lamp 820 or a driver integrated circuit.

[0070] See Figure 7 In scenarios involving flash lamp temperature detection, NTC thermistors are mounted on the FPC surface via a nickel-gold layer or OSP 940 layer. This causes the NTC thermistors to occupy space on the FPC surface, and they are at risk of cracking during transportation, assembly, and drops, leading to open circuits and device failure, thus reducing overall reliability. Furthermore, due to space constraints, the NTC thermistors are often placed away from the heat source, resulting in sluggish temperature response, distorted detection accuracy, and an inability to accurately reflect the risk of thermal runaway.

[0071] Figure 10 The diagram shows a cross-sectional view of the circuit board of a flash lamp 820 in the prior art. The circuit board is mounted on a bracket 950, and the flash lamp 820 is attached to the side of the circuit board away from the bracket 950. Foam 821 is arranged around the periphery of the flash lamp 820. Figure 10 NTC thermistor R NTC The lateral distance between the flash unit 820 and the flash unit is 'a'. Figure 9 The diagram shown is a cross-sectional view of the circuit board of the flash lamp 820 in this embodiment of the application. The lateral distance between the embedded resistor R and the flash lamp 820 is b. Obviously, b is less than a, which allows the embedded resistor R to be closer to the heating element, thereby improving the accuracy of temperature detection without occupying FPC surface space.

[0072] In some embodiments of this application, the heating element is a power transmission element or a power storage element. Optionally, the power transmission element is a wireless charging coil 840, and the power storage element is a battery 830.

[0073] See Figure 5 The electronic device also includes a motherboard 920 and a sub-board 930. The motherboard 920 and the sub-board 930 are electrically connected through a flexible circuit board (FPC). An embedded resistor is placed in the FPC and positioned above the battery 830 to detect the temperature of the battery 830.

[0074] See Figure 6 and Figure 12 In scenarios involving the detection of battery or wireless charging coil temperature, the existing NTC thermistor R... NTC By attaching the NTC thermistor to the FPC surface using a nickel-gold layer or an OSP layer 940, the NTC thermistor occupies space on the FPC surface, and the NTC thermistor R... NTCThere is a risk of cracking during transportation, assembly, and drop testing, which can lead to open circuits, component failures, and reduced overall reliability. On the other hand, due to space constraints, R... NTC The placement of the thermistor is often off-center from the heat source, resulting in sluggish temperature response, distorted detection accuracy, and an inability to accurately reflect the risk of thermal runaway. Furthermore, the NTC thermistor R is housed in a slot on the 910 mid-frame. NTC This design adds extra machining steps and requires precise alignment of the slots during assembly. Any deviation can easily lead to jamming or damage to components, increasing manufacturing costs and process complexity. For example... Figure 12 In the circuit board, the vertical stacking thickness is e, and the NTC thermistor R... NTC The straight-line distance from battery 830 is c.

[0075] And see Figure 11 The vertical stacking thickness of the circuit board in this application is f, and the NTC thermistor R NTC The straight-line distance from battery 830 is d. Clearly, f is less than e, and d is less than c. Therefore, compared to the FPC surface-mount NTC thermistor solution, if the package thickness is 0.2 / 0.3 mm, the solution proposed in this application... Figure 11 and Figure 12 In this design, the distance from e to f is shortened by at least 0.2 mm, freeing up vertical stacking space and providing greater freedom for the design of thinner and lighter electronic devices. Furthermore, the distance from c to d is shortened by 0.1~0.2 mm, allowing the embedded resistor R to be placed closer to the power transmission or storage components, thus improving the accuracy and sensitivity of temperature detection.

[0076] In some embodiments, the integration can be extended to multiple embedded passive components, such as embedded resistors and embedded capacitors, on the circuit board to achieve integrated temperature measurement and filtering functions. By introducing an array of embedded resistors, the temperature distribution in different areas can be detected, and by introducing embedded capacitors, signal filtering can be achieved, improving anti-interference capabilities.

[0077] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0078] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A circuit board, characterized in that, include: Conductive substrate; A temperature-sensitive element, formed of a thermistor material and embedded inside the conductive substrate, wherein the equivalent resistance of the temperature-sensitive element changes with temperature; At least two detection electrodes are electrically connected to the temperature-sensitive element and are used to output the equivalent resistance value of the temperature-sensitive element to an external circuit.

2. The circuit board according to claim 1, characterized in that, The conductive substrate includes: Substrate insulation layer; The conductive layer includes a first conductive layer and a second conductive layer, which are respectively formed on two opposite surfaces of the substrate insulating layer.

3. The circuit board according to claim 2, characterized in that, The temperature-sensitive element is disposed between the first conductive layer and the substrate insulating layer; The at least two detection electrodes include a first detection electrode and a second detection electrode; the first detection electrode is formed by a first portion of the first conductive layer and is electrically connected to a first end of the temperature-sensitive element; the second detection electrode is formed by a second portion of the first conductive layer and is electrically connected to a second end of the temperature-sensitive element. The first and second portions of the first conductive layer are insulated from each other.

4. The circuit board according to claim 2, characterized in that, A through-hole is formed on the substrate insulating layer, and the thermosensitive material is filled into the through-hole to form the temperature sensitive element; The at least two detection electrodes include a first detection electrode and a second detection electrode; the first detection electrode is formed from a portion of the first conductive layer and is electrically connected to a first end of the temperature-sensitive element; the second detection electrode is formed from a portion of the second conductive layer and is electrically connected to a second end of the temperature-sensitive element.

5. The circuit board according to claim 2, characterized in that, A cavity is formed inside the substrate insulating layer, and a first channel and a second channel are formed in the thickness portion between the cavity and the surface of the substrate insulating layer; The temperature-sensitive element is installed inside the cavity; The at least two detection electrodes include a first detection electrode and a second detection electrode; the first detection electrode is formed by a first conductive region in the conductive layer and is electrically connected to a first end of the temperature-sensitive element through the first channel; the second detection electrode is formed by a second conductive region in the conductive layer and is electrically connected to a first end of the temperature-sensitive element through the second channel.

6. The circuit board according to claim 5, characterized in that, Both the first conductive region and the second conductive region are formed in the first conductive layer; or, The first conductive region is formed in the first conductive layer, and the second conductive region is formed in the second conductive layer.

7. The circuit board according to claim 5, characterized in that, The cavity includes a first space, a second space, and a third space, with the second space sandwiched between the first space and the third space; The temperature-sensitive element is disposed in the second space, and the first space, the third space, the first channel and the second channel are filled with conductive material; The conductive layer is electrically connected to the temperature-sensitive element through the conductive material.

8. The circuit board according to claim 2, characterized in that, The circuit board also includes: A first insulating covering layer is located on a first side of the conductive substrate; A second insulating cover layer is located on the second side of the conductive substrate; A first adhesive layer is sandwiched between the first insulating cover layer and a first side of the conductive substrate; The second adhesive layer is sandwiched between the second insulating cover layer and the second side of the conductive substrate.

9. An electronic device, characterized in that, The circuit board includes any one of claims 1 to 8; and a heating element, wherein a temperature-sensitive element in the circuit board is used to detect the heat generated by the heating element.

10. The electronic device according to claim 9, characterized in that, The heating element includes the image sensor of the camera module or a driver integrated circuit.

11. The electronic device according to claim 9, characterized in that, The heating element is either the light-emitting element of a flash lamp or a driver integrated circuit.

12. The electronic device according to claim 9, characterized in that, The heating element is an energy transmission element or an energy storage element.

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