Detection unit, camera module and electronic device

Abstract

The embodiments of the present application relate to the technical field of detection. Provided are a detection unit, a camera module and an electronic device. The detection unit comprises at least two magnetic-field sensors, which are connected in parallel. Output ends of the at least two magnetic-field sensors are electrically connected to form a connection node, and an input end of an operational amplification module is electrically connected to the connection node. In the embodiments of the present application, it is not necessary to provide a plurality of operational amplification modules and make same be electrically connected to a plurality of magnetic-field sensors in a manner of corresponding to each other on a one-to-one basis, thereby reducing the number of operational amplification modules, and reducing the cost of a camera module. In addition, an operational amplification module can acquire, by means of a connection point, the average value of the output voltages from the at least two magnetic-field sensors, and it is not necessary to perform digital calculation on the output voltages from the at least two magnetic-field sensors by means of a digital device, thereby shortening the time required for acquiring the average value of the output voltages from the at least two magnetic-field sensors, and increasing the response speed of the camera module during closed-loop automatic focusing.

Description

Detection units, camera modules and electronic equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on August 16, 2023, with application number 202311037332.2 and application name “Detection unit, camera module and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the technical field of detection, and in particular to a detection unit, a camera module, and an electronic device. Background Art

[0003] In the related art, the cost of the camera module is relatively high, and the response speed during closed-loop autofocus is relatively slow.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a detection unit, a camera module, and an electronic device for reducing the cost of the camera module and improving the response speed of the camera module during closed-loop autofocus.

[0006] In order to achieve the above objectives, the following technical solutions are provided:

[0007] In one aspect, embodiments of the present application provide a detection unit. The detection unit includes at least two magnetic field sensors connected in parallel. Outputs of the at least two magnetic field sensors are electrically connected to form a connection node, and an input of an operational amplifier module is electrically connected to the connection node.

[0008] In an embodiment of the present application, the number of magnetic field sensors is set to at least two, and the at least two magnetic field sensors can respectively detect the magnetic field strength in the detection direction at their current position in the magnetic field, and convert the detected magnetic field strength into a corresponding voltage signal, thereby increasing the width of the linear region in the relationship curve between the distance between the lens and the image sensor and the magnetic field strength detected by the magnetic field sensor, thereby increasing the focusing range of the lens.

[0009] It can be understood that the connection node is not an actual component, but rather represents a junction point of related electrical connections. In other words, the connection node is a node formed by the junction point of the output terminals of at least two magnetic field sensors being electrically connected. The output terminals of at least two magnetic field sensors are electrically connected to form a connection node, and the voltage value of the connection node can be equal to the average value of the output voltages of the at least two magnetic field sensors. The input terminal of the operational amplifier module is electrically connected to the connection node, so that the operational amplifier module can obtain the average value of the output voltages of the at least two magnetic field sensors through the connection node and amplify the average value of the output voltages of the at least two magnetic field sensors. In this way, there is no need to set up multiple operational amplifier modules to be electrically connected to multiple magnetic field sensors in a one-to-one correspondence, thereby reducing the number of operational amplifier modules, reducing the cost of the camera module, and reducing the area occupied by the operational amplifier module on the circuit board (or in the chip).

[0010] In addition, the output ends of at least two magnetic field sensors are electrically connected to form a connection node, and the output voltages of the at least two magnetic field sensors are averaged through a hardware circuit, so that the digital processing module does not need to perform digital calculations (such as summing or averaging) on ​​the output voltages of the at least two magnetic field sensors, thereby saving the computing power of the digital processing module, reducing the delay of the digital processing module, and reducing the time required for obtaining the average value of the output voltages of the at least two magnetic field sensors. This improves the response speed of the camera module during closed-loop autofocus, thereby improving the closed-loop autofocus efficiency of the camera module.

[0011] That is, by adopting the above-mentioned setting method, the camera module can achieve low-cost, high-efficiency and long-distance (long focusing stroke) closed-loop autofocus.

[0012] In some possible implementations, the magnetic field sensor has a first output terminal and a second output terminal. The first output terminals of at least two magnetic field sensors are electrically connected to form a first connection node, and the second output terminals of at least two magnetic field sensors are electrically connected to form a second connection node. This arrangement allows the voltage value of the first connection node to be equal to the average of the output voltages of the first output terminals of the at least two magnetic field sensors, and the voltage value of the second connection node to be equal to the average of the output voltages of the second output terminals of the at least two magnetic field sensors. This allows the hardware circuit to calculate the average of the output voltages of the first output terminals of the at least two magnetic field sensors and the output voltages of the second output terminals of the at least two magnetic field sensors, saving computing power and reducing latency in the digital processing module. This reduces the time required for closed-loop autofocus of the camera module and improves the efficiency of the closed-loop autofocus of the camera module.

[0013] In some possible implementations, the detection unit further includes at least two current-limiting elements. The first ends of the at least two current-limiting elements are electrically connected to the output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of the at least two current-limiting elements are electrically connected to a connection node. The current-limiting elements are used to limit the current value of the current flowing between the output ends of any two magnetic field sensors. This configuration enables the current-limiting elements to be connected in series between the output ends of the magnetic field sensors and the connection node, thereby limiting the current value of the current flowing between the output ends of the magnetic field sensors and the connection node. In other words, it limits the current value of the current flowing between the output ends of any two magnetic field sensors. This reduces the risk of current flowing from the output end of one magnetic field sensor (e.g., the first magnetic field sensor) through the connection node to the output end of another magnetic field sensor (a magnetic field sensor other than the first magnetic field sensor, e.g., the second magnetic field sensor), thereby reducing the impact on the output voltage of each magnetic field sensor after the output ends of the at least two magnetic field sensors are electrically connected to form a connection node. This ensures that the voltage value of the connection node is approximately the same as the average value of the output voltages of the at least two magnetic field sensors when they are respectively electrically connected to the at least two operational amplifier modules, thereby improving the reliability of the detection unit.

[0014] In some possible implementations, the current-limiting element includes a first sub-element and a second sub-element. The first ends of at least two of the first sub-elements are electrically connected to the first output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of the at least two first sub-elements are electrically connected to the first connection node. The first ends of at least two of the second sub-elements are electrically connected to the second output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of the at least two second sub-elements are electrically connected to the second connection node. By providing the first sub-element, the risk of current flowing from the first output end of one magnetic field sensor (e.g., the first magnetic field sensor) via the first connection node into the first output end of another magnetic field sensor (a magnetic field sensor other than the first magnetic field sensor, e.g., the second magnetic field sensor) can be reduced. By providing the second sub-element, the risk of current flowing from the second output end of one magnetic field sensor (e.g., the first magnetic field sensor) via the second connection node into the second output end of another magnetic field sensor (a magnetic field sensor other than the first magnetic field sensor, e.g., the second magnetic field sensor) can be reduced. This reduces the mutual influence between the first output ends of at least two magnetic field sensors and the mutual influence between the second output ends of at least two magnetic field sensors. In other words, it reduces the impact on the output voltage of each magnetic field sensor after the output ends of the at least two magnetic field sensors are electrically connected to form a connection node. This also reduces the impact of the reduced sensitivity and linearity of the detection unit caused by different output internal resistance values ​​of the at least two magnetic field sensors after the output ends of the at least two magnetic field sensors are electrically connected.

[0015] In some possible implementations, the first sub-element includes a first resistor, the second sub-element includes a second resistor, and the resistance of the first resistor is equal to the resistance of the second resistor; or the first sub-element includes multiple first resistors, which are electrically connected. The second sub-element includes multiple second resistors, which are electrically connected. The resistance of the multiple first resistors after being electrically connected is equal to the resistance of the multiple second resistors after being electrically connected. This arrangement enables the first and second sub-element to function as current limiters. Furthermore, it simplifies the calculation process for calculating the amplification factor of the operational amplifier module, improving the ease of use of the detection unit.

[0016] In some possible implementations, the operational amplifier module includes a differential amplifier circuit. The differential amplifier circuit is configured to: obtain an average voltage value of the first output terminals of at least two magnetic field sensors, and an average voltage value of the second output terminals of at least two magnetic field sensors. Calculate the difference between the average voltage value of the first output terminals of the at least two magnetic field sensors and the average voltage value of the second output terminals of the at least two magnetic field sensors to obtain an average value of the output voltages of the at least two magnetic field sensors. Amplify the average value of the output voltages of the at least two magnetic field sensors. The differential amplifier circuit can amplify and output the average value of the output voltages of the at least two magnetic field sensors (the output voltage of the magnetic field sensor is the difference between the voltage value of the first output terminal of the magnetic field sensor and the voltage value of the second output terminal of the magnetic field sensor), thereby improving the accuracy of determining the distance between the lens and the image sensor based on the output voltage of the operational amplifier.

[0017] In some possible implementations, the differential amplifier circuit includes an operational amplifier, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The resistance of the third resistor is equal to the resistance of the fourth resistor. The resistance of the fifth resistor is equal to the resistance of the sixth resistor. A first end of the third resistor is electrically connected to the non-inverting input of the operational amplifier, and a second end of the third resistor is electrically connected to the first connection node. A first end of the fourth resistor is electrically connected to the inverting input of the operational amplifier, and a second end of the fourth resistor is electrically connected to the second connection node. A first end of the fifth resistor is electrically connected to the non-inverting input of the operational amplifier, and a second end of the fifth resistor is electrically connected to the power supply or ground. A first end of the sixth resistor is electrically connected to the inverting input of the operational amplifier, and a second end of the sixth resistor is electrically connected to the output of the operational amplifier. It is understandable that by electrically connecting the second end of the fifth resistor to the power supply or ground, current flowing out of the first output terminals of at least two magnetic field sensors, after flowing through the third and fifth resistors, can flow to the power supply or ground, thereby increasing the flexibility of the circuit structure. In addition, the non-inverting input terminal of the operational amplifier is electrically connected to the first connection node, and the inverting input terminal of the operational amplifier is electrically connected to the second connection node, so that the operational amplifier can obtain the average value of the output voltages of the first output terminals of the at least two magnetic field sensors and the average value of the output voltages of the second output terminals of the at least two magnetic field sensors, and perform a difference between the average value of the output voltages of the first output terminals of the at least two magnetic field sensors and the average value of the output voltages of the second output terminals of the at least two magnetic field sensors to obtain the average value of the output voltages of the at least two magnetic field sensors.

[0018] In some possible implementations, the resistance of the third resistor and the fourth resistor are significantly greater than the output internal resistance of the magnetic field sensor. This configuration can reduce the impact of the output internal resistance of the magnetic field sensor on the amplification factor of the operational amplifier module, thereby improving the ease of use of the detection unit.

[0019] In some possible implementations, the resistance of the third resistor and the resistance of the fourth resistor are a first resistance, the resistance of the fifth resistor and the resistance of the sixth resistor are a second resistance, and the second resistance is m times the first resistance, where m is a positive number and greater than 1. This configuration enables the operational amplifier module to amplify the difference between the voltage value at the non-inverting input terminal of the operational amplifier and the voltage value at the inverting input terminal of the operational amplifier. In other words, the operational amplifier module can amplify the difference between the average output voltage of the first output terminals of the at least two magnetic field sensors and the average output voltage of the second output terminals of the at least two magnetic field sensors, thereby increasing the output voltage of the operational amplifier module and improving the accuracy of determining the distance between the lens and the image sensor based on the output voltage of the operational amplifier module.

[0020] In some possible implementations, the differential amplifier circuit is electrically connected to a power supply terminal (for example, the second end of the fifth resistor is electrically connected to the power supply terminal). The voltage value of the power supply terminal is -k times the average of the bias voltages of the at least two magnetic field sensors. Here, k is the amplification factor of the operational amplifier module. This configuration enables the power supply terminal to compensate for the bias voltages of the at least two magnetic field sensors, reducing the impact of the bias voltages of the at least two magnetic field sensors on the input voltage and output voltage of the operational amplifier module, allowing the operational amplifier module to continuously operate within the linear range, thereby ensuring the focus accuracy of the camera module.

[0021] In some possible implementations, the detection unit further includes a first circuit board, the first circuit board including conductive traces. The magnetic field sensor and the current-limiting element are electrically connected via the conductive traces. This arrangement enables the magnetic field sensor and the current-limiting element to be located on the same circuit board (the first circuit board) and electrically connected via the conductive traces on the circuit board, thereby reducing the distance between the magnetic field sensor and the current-limiting element and facilitating miniaturization of the detection unit.

[0022] In some possible implementations, the resistances of at least two magnetic field sensors are equal, and the power input terminals of at least two magnetic field sensors are electrically connected to the same power supply; or, the number of power supplies is at least two, and the power input terminals of at least two magnetic field sensors are electrically connected to the at least two power supplies in a one-to-one correspondence. When the resistances of at least two magnetic field sensors are equal, setting the power input terminals of at least two magnetic field sensors to be electrically connected to the same power supply reduces the number of power supplies, reduces the cost of the camera module, and reduces the area occupied by the power supply on the circuit board (or within the chip). Or, setting the number of power supplies to at least two, and the power input terminals of at least two magnetic field sensors to be electrically connected to the at least two power supplies in a one-to-one correspondence can reduce the mutual influence of the at least two power supplies when supplying power to the at least two magnetic field sensors, thereby improving the accuracy of the camera module.

[0023] In some possible implementations, the output of the operational amplifier module is electrically connected to the input of the digital processing module. The digital processing module is configured to generate a control signal based on the output of the operational amplifier module. This configuration enables the digital processing module to obtain the output voltage of the operational amplifier module and, based on the output voltage of the operational amplifier module, determine the distance between the lens and the image sensor to generate a control signal. This control signal can then be used to control other components (e.g., the driver) based on the control signal, thereby achieving closed-loop autofocus for the camera module.

[0024] On the other hand, an embodiment of the present application provides a camera module. The camera module includes a lens, an image sensor, and a detection unit. The detection unit is used to detect the distance between the lens and the image sensor.

[0025] The camera module provided in the embodiment of the present application includes the detection unit as described above, and therefore has all the beneficial effects described above, which will not be repeated here.

[0026] In some possible implementations, the detection unit includes an operational amplifier module, the input of which is electrically connected to the connection node; or the camera module further includes an operational amplifier module, the input of which is electrically connected to the connection node. This configuration enables the operational amplifier module to amplify the average of the output voltages of at least two magnetic field sensors without requiring additional averaging calculations, thereby improving the convenience of determining the distance between the lens and the image sensor and shortening the time required for the camera module to focus. Furthermore, the configuration in which the detection unit includes the operational amplifier module, or the configuration in which the camera module includes the operational amplifier module, can increase the flexibility of the configuration of electronic components (e.g., the operational amplifier module) within the camera module to meet different usage requirements.

[0027] In some possible implementations, the detection unit further includes a power supply, which is electrically connected to the power input terminal of the magnetic field sensor; or the camera module further includes a power supply, which is electrically connected to the power input terminal of the magnetic field sensor. This configuration enables the power supply to power the magnetic field sensor, thereby enabling the magnetic field sensor to operate normally. Furthermore, the detection unit can include a power supply, or the camera module can include a power supply, which can increase the flexibility of the configuration of electronic components (such as the power supply) within the camera module and meet different usage requirements.

[0028] In some possible implementations, the camera module further includes a driver configured to drive the lens to move. The detection unit further includes a digital processing module, wherein the input of the digital processing module is electrically connected to the output of the operational amplifier module, and the output of the digital processing module is electrically connected to the driver. Alternatively, the camera module further includes a digital processing module, wherein the input of the digital processing module is electrically connected to the output of the operational amplifier module, and the output of the digital processing module is electrically connected to the driver. The input of the digital processing module is electrically connected to the output of the operational amplifier module, enabling the digital processing module to obtain the output voltage of the operational amplifier module and determine the distance between the lens and the image sensor based on the output voltage of the operational amplifier module to generate a control signal. The output of the digital processing module is electrically connected to the driver, enabling the digital processing module to control the driver based on the control signal, thereby enabling the driver to drive the lens to move based on the distance between the lens and the image sensor, enabling the camera module to achieve closed-loop autofocus, thereby improving the accuracy and reliability of the camera module during focusing. Setting the detection unit may include a digital processing module, or setting the camera module may include a digital processing module, which can improve the setting flexibility of electronic devices (such as digital processing modules) in the camera module and meet different usage requirements.

[0029] In another aspect, an embodiment of the present application provides an electronic device, which includes a housing and the camera module described above, wherein the camera module is located in the housing, and a portion of the camera module is exposed to the housing.

[0030] The electronic device provided by the embodiments of the present application includes the camera module as described above, and therefore has all the beneficial effects described above, which will not be repeated here. In addition, the camera module is located within the housing, so that the housing can protect the camera module and reduce the risk of damage to the camera module. A portion of the camera module is exposed to the housing, allowing light to reach the camera module, avoiding obstruction of the camera module by the housing, and enabling the camera module to perform image acquisition functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of the structure of an electronic device provided in some embodiments of the present application;

[0032] FIG2 is a schematic structural diagram of a camera module provided in some embodiments of the present application;

[0033] FIG3 is a schematic structural diagram of a camera module provided by some embodiments of the present application without showing a magnet;

[0034] FIG4 is a schematic diagram showing the positional relationship among a lens, a magnet, and a magnetic field sensor according to some embodiments of the present application;

[0035] FIG5 is an equivalent circuit diagram of a Hall sensor provided in some embodiments of the present application;

[0036] FIG6 is a schematic diagram of the connection relationship of camera modules provided in some embodiments of the present application;

[0037] FIG7 is a schematic diagram of a circuit topology of a camera module provided in some embodiments of the present application;

[0038] FIG8 is a schematic diagram of a circuit topology of a camera module provided in some other embodiments of the present application;

[0039] FIG9 is a schematic diagram of a curve showing the magnetic field strength detected by a magnetic field sensor and changes with the distance between a lens and an image sensor according to some embodiments of the present application;

[0040] FIG10 is a schematic diagram showing the positional relationship among a lens, a magnet, and a magnetic field sensor provided in other embodiments of the present application;

[0041] FIG11 is a schematic diagram of a curve showing the magnetic field intensity detected by the magnetic field sensor and the change with the distance between the lens and the image sensor according to other embodiments of the present application;

[0042] FIG12 is a schematic diagram of circuit topology of camera modules provided in some other embodiments of the present application;

[0043] FIG13 is a schematic diagram of the connection relationship of camera modules provided in other embodiments of the present application;

[0044] FIG14 is a schematic diagram showing the connection relationship of camera modules provided in some other embodiments of the present application;

[0045] FIG15 is a schematic diagram of circuit topology of camera modules provided in some other embodiments of the present application;

[0046] FIG16 is a schematic diagram showing the connection relationship of camera modules provided in some other embodiments of the present application;

[0047] FIG17 is a schematic diagram showing the connection relationship of camera modules provided in some other embodiments of the present application;

[0048] FIG18 is a schematic diagram of circuit topology of camera modules provided in some other embodiments of the present application;

[0049] FIG19 is a schematic diagram of circuit topology of camera modules provided in some other embodiments of the present application;

[0050] FIG20 is a schematic diagram showing the connection relationship of camera modules provided in some other embodiments of the present application;

[0051] FIG21 is a schematic diagram showing the connection relationship of camera modules provided in some other embodiments of the present application;

[0052] FIG22 is a schematic diagram of a circuit topology of a camera module provided in some other embodiments of the present application;

[0053] FIG23 is a schematic diagram of circuit topology of camera modules provided in some other embodiments of the present application;

[0054] FIG24 is a schematic diagram of a curve showing the magnetic field strength detected by the magnetic field sensor and changes with the distance between the lens and the image sensor provided in some other embodiments of the present application. DETAILED DESCRIPTION

[0055] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0056] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and its other forms, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open and inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" are intended to indicate that the specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present application. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0057] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0058] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0059] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0060] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within an acceptable deviation range, wherein the acceptable deviation range is as determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality can be, for example, that the difference between the two equals is less than or equal to 5% of either one.

[0061] Figure 1 is a schematic diagram of the structure of an electronic device provided in some embodiments of the present application. Figure 2 is a schematic diagram of the structure of a camera module provided in some embodiments of the present application. Figure 3 is a schematic diagram of the structure of a camera module provided in some embodiments of the present application without the magnet. Figure 4 is a schematic diagram of the positional relationship between the lens, magnet, and magnetic field sensor provided in some embodiments of the present application.

[0062] As shown in FIG1 , an embodiment of the present application provides an electronic device 300. The electronic device 300 may be an electronic device with an image acquisition function, such as a mobile phone, a computer, a camera, a smartwatch, a wearable device, or a video camera. It is understood that the embodiment of the present application does not further limit the type of the electronic device 300.

[0063] As shown in Figure 1, the electronic device 300 may include a housing 301 and a camera module 200, wherein the camera module 200 is located within the housing 301. It is understood that the housing 301 can enclose a storage space, the camera module 200 is located within the storage space enclosed by the housing 301, and a portion of the camera module 200 can be exposed to the housing 301.

[0064] The camera module 200 is located within the housing 301, so that the housing 301 can protect the camera module 200 and reduce the risk of damage to the camera module 200. A portion of the camera module 200 is exposed to the housing 301, so that light can reach the camera module 200, avoiding obstruction of the camera module 200 by the housing 301, and enabling the camera module 200 to perform image acquisition functions.

[0065] In some examples, the electronic device 300 may include one camera module 200. In other examples, the electronic device 300 may also include multiple camera modules 200. The embodiments of the present application do not further limit the number of camera modules 200 included in the electronic device 300.

[0066] In some examples, as shown in Figures 2 and 3, the camera module 200 may include a housing 202 and a lens 221. For example, the lens 221 may include one or more of a convex lens, a concave lens, or other optical lenses. The lens 221 has an optical axis, which may extend along a first direction X. Referring to Figure 1, the housing 301 of the electronic device 300 may have a through hole Q, and light passing through the through hole Q may directly illuminate the lens 221, or the light passing through the through hole Q may also be reflected to the lens 221.

[0067] As shown in FIG4 , the camera module 200 may further include an image sensor 201, which may be located within a housing 202. For example, the image sensor 201 may be disposed on a circuit board (e.g., a PCB board, which is the full name of the printed circuit board in English and the Chinese name of the printed circuit board in Chinese). The circuit board may be connected to the housing 202 by gluing or bolting, so that the image sensor 201 is connected to the housing 202 via the circuit board.

[0068] As shown in FIG4 , along a first direction X (i.e., along the direction extending along the optical axis of the lens 221), the image sensor 201 is located on one side of the lens 221. Light irradiated onto the lens 221 can be reflected or refracted by the lens 221 and irradiated onto the image sensor 201. The image sensor 201 can obtain image information from the light irradiated onto it, thereby enabling the camera module 200 to realize an image acquisition function.

[0069] It is understandable that when capturing image information, the lens 221 needs to move relative to the image sensor 201 along the extension direction of the optical axis (the first direction X) to achieve focusing, so that the camera module 200 can clearly capture image information at different positions along the first direction X. To achieve the focusing function, as shown in Figures 2 and 3, the camera module 200 may further include a motor 210, which may be located within the housing 202.

[0070] The motor 210 may include a driving unit 211 and a detection unit 100, that is, the camera module 200 may include the driving unit 211 and the detection unit 100. The driving unit 211 is used to drive the lens 221 to move (move along the first direction X), and the detection unit 100 is used to detect the distance between the lens 221 and the image sensor 201. In this way, the driving unit 211 can drive the lens 221 to move along the first direction X according to the distance between the lens 221 and the image sensor 201, thereby enabling the camera module 200 to achieve closed-loop autofocus (English full name: Auto Focus, English abbreviation: AF), thereby improving the performance of the camera module 200.

[0071] In some examples, the camera module 200 may include a magnet 222 , and the detection unit 100 may include a magnetic field sensor 101 .

[0072] For example, the magnet 222 can be a single magnet or an array of multiple magnets. The dotted line in Figure 4 represents the magnetic field generated by the magnet 222, and the arrow on the dotted line represents the direction of the magnetic field. It is understandable that Figure 4 only shows one magnet 222 and the magnetic field generated by the magnet 222, and does not further limit the number of magnets 222 and the magnetic field strength generated by the magnet 222 in the embodiments of the present application.

[0073] It is understood that the magnetic field sensor 101 has a detection direction (a specific direction, such as direction H in FIG. 4 ). The magnetic field sensor 101 can detect the magnetic field strength in the detection direction at its current position in the magnetic field and convert the detected magnetic field strength into a corresponding electrical signal, such as a voltage signal. The output voltage of the magnetic field sensor 101 can be proportional to the magnetic field strength detected by the magnetic field sensor 101.

[0074] For example, the magnetic field sensor 101 can be any one of a Hall sensor, a TMR (English full name: Tunnel Magneto Resistance, Chinese name: tunnel magnetoresistance) sensor, a GMR (English full name: Giant Magneto Resistive, Chinese name: giant magnetoresistance) sensor and an AMR (English full name: Anisotropy of Magneto Resistance, Chinese name: anisotropic magnetoresistance) sensor.

[0075] In some examples, one of the magnet 222 and the magnetic field sensor 101 may be fixed relative to the lens 221, and the other may be fixed relative to the image sensor 201. When the lens 221 moves along the first direction X, the relative position between the magnet 222 and the magnetic field sensor 101 changes, causing the position of the magnetic field sensor 101 in the magnetic field to change, thereby causing the magnetic field intensity in the detection direction of the magnetic field sensor 101 to change, and the output voltage of the magnetic field sensor 101 to change.

[0076] It can be understood that during the focusing process, the magnetic field strength detected by the magnetic field sensor 101 corresponds one-to-one to the distance between the lens 221 and the image sensor 201, and the magnetic field strength detected by the magnetic field sensor 101 corresponds one-to-one to the output voltage of the magnetic field sensor 101, so that the output voltage of the magnetic field sensor 101 can correspond one-to-one to the distance between the lens 221 and the image sensor 201, and thus the distance between the lens 221 and the image sensor 201 can be obtained according to the output voltage of the magnetic field sensor 101.

[0077] For example, during the production process of the camera module 200, the correspondence between the output voltage of the magnetic field sensor 101 and the distance between the lens 221 and the image sensor 201 can be calibrated. Specifically, the distance between the lens 221 and the image sensor 201 is obtained using laser ranging, and different output voltages of the magnetic field sensor 101 are obtained when the distances between the lens 221 and the image sensor 201 are different. A one-to-one correspondence is established between the output voltage of the magnetic field sensor 101 and the distance between the lens 221 and the image sensor 201 to improve the linearity of the relationship curve between the two, thereby improving the accuracy and reliability of the closed-loop autofocus of the camera module 200.

[0078] It is understandable that in different camera modules 200 , when the distance between the lens 221 and the image sensor 201 is the same, the output voltage of the magnetic field sensor 101 may be the same or different.

[0079] The embodiments of the present application are described by taking the magnet 222 and the lens 221 as being relatively fixed, the magnetic field sensor 101 and the housing 202 and the image sensor 201 as examples.

[0080] It is understandable that the lens 221 and the magnet 222 are relatively fixed, that is, the lens 221 and the magnet 222 can remain relatively stationary. In some examples, the lens 221 can be connected to the magnet 222, such as a fixed connection or a detachable connection, so that the lens 221 and the magnet 222 can be relatively fixed. In other examples, the camera module 200 may include a fixing member (not shown in the figure), and the lens 221 and the magnet 222 are respectively connected to the fixing member, so that the lens 221 and the magnet 222 can be relatively fixed.

[0081] In some examples, the magnet 222 can be located on one side of the lens 221 along the second direction Y. In other examples, the magnet 222 can also be located on one side of the lens 221 along the third direction Z. This arrangement can prevent the magnet 222 from blocking light. It is understood that the second direction Y intersects with the first direction X. For example, the second direction Y and the first direction X can be perpendicular or approximately perpendicular. The third direction Z intersects with the plane containing the first direction X and the second direction Y. For example, the third direction Z can be perpendicular or approximately perpendicular to the plane containing the first direction X and the second direction Y.

[0082] In some examples, there may be multiple magnets 222. For example, the multiple magnets 222 may be located on both sides of the lens 221 along the second direction Y; or, the multiple magnets 222 may be located on both sides of the lens 221 along the third direction Z; or, a portion of the multiple magnets 222 may be located on one or both sides of the lens 221 along the second direction Y, and another portion of the multiple magnets 222 may be located on one or both sides of the lens 221 along the third direction Z.

[0083] In some examples, as shown in FIG4 , the magnetic field sensor 101 is connected to the housing 202 and is located on one side of the lens 221 along the second direction Y (or along the third direction Z), so that the magnetic field sensor 101 can be fixed relative to the image sensor 201. In some examples, the magnetic field sensor 101 and the magnet 222 are located on the same side of the lens 221 to improve the accuracy of the magnetic field sensor 101 in detecting magnetic field strength.

[0084] In some examples, the driving portion 211 of the motor 210 may directly drive the lens 221 to move along the first direction X. In other examples, the driving portion 211 of the motor 210 may also drive the magnet 222 to move along the first direction X, thereby driving the lens 221 to move along the first direction X via the magnet 222 .

[0085] When the motor 210 drives the lens 221 to move via the magnet 222, the magnet 222 driven by the motor 210 and the magnet 222 detected by the detection unit 100 can be the same magnet 222 to simplify the structure of the camera module 200. Alternatively, the magnet 222 driven by the motor 210 and the magnet 222 detected by the detection unit 100 can be different magnets 222. In this case, one of the magnets 222 can be located on one side of the lens 221 along the second direction Y, and the other magnet 222 can be located on one side of the lens 221 along the third direction Z to reduce the mutual influence between the motor 210 and the magnetic field sensor 101.

[0086] In some examples, the drive unit 211 may include a motor coil, and a magnetic field can be generated around the motor coil by energizing the motor coil. It is understood that when the current flowing through the motor coil changes, the magnetic field generated by the motor coil can change. The magnetic field generated by the motor coil interacts with the magnetic field of the magnet 222 (mutual attraction or mutual repulsion), allowing the motor coil to drive the magnet 222 to move along the first direction X, so that the magnet 222 can drive the lens 221 to move along the first direction X.

[0087] For example, the number of motor coils can be two, and the two motor coils respectively drive the two magnets 222 located on both sides of the lens 221 along the second direction Y to move, so that the two magnets 222 located on both sides of the lens 221 along the second direction Y can jointly drive the lens 221 to move along the first direction X, so as to improve the stability and reliability of the driving unit 211 when driving the lens 221 to move.

[0088] In other examples, the driving unit 211 may also include a motor, and the motor provides a driving force to enable the lens 221 to move along the first direction X to achieve closed-loop autofocus.

[0089] Figure 5 is an equivalent circuit diagram of a Hall effect sensor provided in some embodiments of the present application. Figure 6 is a schematic diagram of the connection relationship of a camera module provided in some embodiments of the present application. Figure 7 is a schematic diagram of the circuit topology of a camera module provided in some embodiments of the present application. Figure 8 is a schematic diagram of the circuit topology of a camera module provided in other embodiments of the present application.

[0090] Taking the magnetic field sensor 101 as a Hall effect sensor as an example, as shown in FIG5 , the Hall effect sensor can be equivalent to a first equivalent resistor Ra, a second equivalent resistor Rb, a third equivalent resistor Rc, and a fourth equivalent resistor Rd. It should be understood that FIG5 is an equivalent circuit diagram of the Hall effect sensor, not the actual circuit structure within the Hall effect sensor.

[0091] As shown in FIG5 , a first end of the first equivalent resistor Ra is electrically connected to a first end of the third equivalent resistor Rc, a second end of the first equivalent resistor Ra is electrically connected to a first end of the second equivalent resistor Rb, a second end of the third equivalent resistor Rc is electrically connected to a first end of the fourth equivalent resistor Rd, and a second end of the second equivalent resistor Rb is electrically connected to a second end of the fourth equivalent resistor Rd.

[0092] As shown in Figure 5, the first end of the first equivalent resistor Ra and the first end of the third equivalent resistor Rc can be the first power input terminal 101a1 of the magnetic field sensor 101 (Hall sensor), and the second end of the second equivalent resistor Rb and the second end of the fourth equivalent resistor Rd can be the second power input terminal 101a2 of the magnetic field sensor 101 (Hall sensor).

[0093] As shown in FIG6 and FIG7 , the power supply 420 may be electrically connected to the power input terminal 101 a (including the first power input terminal 101 a 1 and the second power input terminal 101 a 2 ) of the magnetic field sensor 101 to supply power to the magnetic field sensor 101 .

[0094] In some examples, the power supply 420 can provide current to the magnetic field sensor 101, and the magnetic field sensor 101 operates in a current drive mode. In this case, the power supply 420 can be a current source or a current sink. When the power supply 420 is a current source, the first power input terminal 101a1 of the magnetic field sensor 101 can be electrically connected to the current source, and the second power input terminal 101a2 of the magnetic field sensor 101 can be grounded. When the power supply 420 is a current sink, the current sink can be electrically connected to the second power input terminal 101a2 of the magnetic field sensor 101.

[0095] In other examples, the power supply 420 can provide voltage to the magnetic field sensor 101, and the magnetic field sensor 101 operates in a voltage drive mode. In this case, the power supply 420 can be a voltage source (English: voltage source) or a voltage sink (English: voltage sink). When the power supply 420 is a voltage source, the first power input terminal 101a1 of the magnetic field sensor 101 can be electrically connected to the voltage source, and the second power input terminal 101a2 of the magnetic field sensor 101 can be grounded. When the power supply 420 is a voltage sink, the voltage sink can be electrically connected to the second power input terminal 101a2 of the magnetic field sensor 101. It is understandable that the power supply 420 can also be other forms of power supply, and the embodiments of the present application do not further limit the circuit structure of the power supply 420.

[0096] In some examples, the detection unit 100 may include a power supply 420 . In other examples, the camera module 200 may include a power supply 420 .

[0097] For example, the detection unit 100 may include a first circuit board (not shown), which may be a PCB (Printed Circuit Board). The first circuit board may include conductive traces. For example, the conductive layer (copper layer) of the circuit board may be etched to form the conductive traces. The magnetic field sensor 101 may be located on the first circuit board of the detection unit 100 and electrically connected to the conductive traces.

[0098] When the detection unit 100 includes a power supply 420, the power supply 420 may be located on the first circuit board of the detection unit 100, and the power supply 420 may be electrically connected to the magnetic field sensor 101 via a conductive trace. When the camera module 200 includes a power supply 420, the power supply 420 may be located on a circuit board other than the first circuit board of the detection unit 100, and may be electrically connected to the magnetic field sensor 101 via a structure such as a cable.

[0099] It is understandable that the power supply 420 is electrically connected to the power input terminal 101a of the magnetic field sensor 101, so that the power supply 420 can supply power to the magnetic field sensor 101, thereby enabling the magnetic field sensor 101 to operate normally. In addition, the detection unit 100 is configured to include the power supply 420, or the camera module 200 is configured to include the power supply 420, which can improve the flexibility of the electronic components (such as the power supply 420) in the camera module 200 and meet different usage requirements. It is understandable that in the embodiment of the present application, the electronic component can be a complete working system including one or more electronic components (capacitors, resistors, switching tubes, etc.), or it can be a subsystem in a working system (such as a chip) including one or more electronic components. As shown in Figure 5, the second end of the first equivalent resistor Ra and the first end of the second equivalent resistor Rb can be the first output terminal 101b1 of the magnetic field sensor 101 (Hall sensor), and the second end of the third equivalent resistor Rc and the first end of the fourth equivalent resistor Rd can be the second output terminal 101b2 of the magnetic field sensor 101 (Hall sensor).

[0100] It is understandable that when the magnetic field strength in the detection direction at the current position of the Hall sensor in the magnetic field changes, the resistance value of at least one of the first equivalent resistor Ra, the second equivalent resistor Rb, the third equivalent resistor Rc, and the fourth equivalent resistor Rd will change, causing the output voltage of the first output terminal 101b1 of the magnetic field sensor 101 or the output voltage of the second output terminal 101b2 of the magnetic field sensor 101 to change. The output voltage of the magnetic field sensor 101 is the difference between the output voltage of the first output terminal 101b1 of the magnetic field sensor 101 and the output voltage of the second output terminal 101b2 of the magnetic field sensor 101. In this way, when the output voltage of the first output terminal 101b1 of the magnetic field sensor 101 or the output voltage of the second output terminal 101b2 of the magnetic field sensor 101 changes, the output voltage of the magnetic field sensor 101 will change.

[0101] As shown in FIG6 , the output terminal 101b of the magnetic field sensor 101 can be electrically connected to the input terminal 410a of the operational amplifier module 410, so that the operational amplifier module 410 can obtain the output voltage of the magnetic field sensor 101 and amplify the output voltage of the magnetic field sensor 101. In some examples, the operational amplifier module 410 can include a PGA (Programmable Gain Amplifier).

[0102] For example, as shown in Figures 7 and 8, the input terminal 410a of the operational amplifier module 410 can be electrically connected to the first output terminal 101b1 of the magnetic field sensor 101 to obtain the output voltage of the first output terminal 101b1 of the magnetic field sensor 101. Furthermore, the input terminal 410a of the operational amplifier module 410 can also be electrically connected to the second output terminal 101b2 of the magnetic field sensor 101 to obtain the output voltage of the second output terminal 101b2 of the magnetic field sensor 101. The operational amplifier module 410 can calculate the difference between the output voltage of the first output terminal 101b1 of the magnetic field sensor 101 and the output voltage of the second output terminal 101b2 of the magnetic field sensor 101, and amplify the difference between the output voltage of the first output terminal 101b1 of the magnetic field sensor 101 and the output voltage of the second output terminal 101b2 of the magnetic field sensor 101. In other words, the operational amplifier module 410 can amplify the output voltage of the magnetic field sensor 101.

[0103] Because the output voltage of the magnetic field sensor 101 corresponds to the distance between the lens 221 and the image sensor 201, the operational amplifier module 410 amplifies the output voltage of the magnetic field sensor 101 so that the output voltage of the operational amplifier module 410 corresponds to the distance between the lens 221 and the image sensor 201. In this way, the distance between the lens 221 and the image sensor 201 can be determined based on the output voltage of the operational amplifier module 410.

[0104] It can be understood that since the output voltage of the operational amplifier module 410 is greater than the output voltage of the magnetic field sensor 101, determining the distance between the lens 221 and the image sensor 201 based on the output voltage of the operational amplifier module 410 can improve the accuracy of determining the distance between the lens 221 and the image sensor 201.

[0105] In some examples, the detection unit 100 may include an operational amplifier module 410 . In other examples, the camera module 200 may include an operational amplifier module 410 .

[0106] When the detection unit 100 includes the operational amplifier module 410, the operational amplifier module 410 can be located on the first circuit board of the detection unit 100, and the operational amplifier module 410 can be electrically connected to the magnetic field sensor 101 via conductive traces. When the camera module 200 includes the operational amplifier module 410, the operational amplifier module 410 can be located on a circuit board other than the first circuit board of the detection unit 100, and can be electrically connected to the magnetic field sensor 101 via a structure such as a cable.

[0107] It can be understood that the detection unit 100 can be set to include an operational amplifier module 410, or the camera module 200 can be set to include an operational amplifier module 410, which can improve the setting flexibility of electronic devices in the camera module 200 (such as the operational amplifier module 410) and meet different usage requirements.

[0108] Under ideal conditions, if the magnetic field strength in the detection direction at the current location of magnetic field sensor 101 in the magnetic field is zero, the output voltage of magnetic field sensor 101 is also zero. If the magnetic field strength in the detection direction at the current location of magnetic field sensor 101 in the magnetic field is p (p represents any magnetic field strength other than zero), the output voltage of magnetic field sensor 101 is q (q represents the voltage value corresponding to the magnetic field strength p, and q is not equal to zero).

[0109] However, magnetic field sensor 101 typically has a bias voltage. This bias voltage is the output voltage of magnetic field sensor 101 when the magnetic field strength in the detection direction at the current location of magnetic field sensor 101 is zero. For example, when the magnetic field strength in the detection direction at the current location of magnetic field sensor 101 is zero, the output voltage of magnetic field sensor 101 is x, where x is the bias voltage of magnetic field sensor 101 (x is not equal to zero). When the magnetic field strength in the detection direction at the current location of magnetic field sensor 101 is p, the output voltage of magnetic field sensor 101 is q + x. This shows that the bias voltage affects the output voltage of magnetic field sensor 101.

[0110] Because the output terminal 101b of the magnetic field sensor 101 is electrically connected to the input terminal 410a of the operational amplifier module 410, the bias voltage of the magnetic field sensor 101 is amplified by the operational amplifier module 410, affecting the input voltage and output voltage of the operational amplifier module 410, thereby affecting the accuracy of determining the distance between the lens 221 and the image sensor 201 based on the output voltage of the operational amplifier module 410.

[0111] Based on this, as shown in Figures 7 and 8, in some examples, the input terminal 410a of the operational amplifier module 410 (e.g., the non-inverting input terminal OP1 of the operational amplifier OP) can be electrically connected to the power supply terminal VDD, which serves to compensate for the bias voltage of the magnetic field sensor 101. For example, the voltage value of the power supply terminal VDD is -k times the bias voltage of the magnetic field sensor 101, where k is the amplification factor of the operational amplifier module 410.

[0112] It can be understood that the output voltage of the operational amplifier module 410 and the magnetic field strength in the detection direction at the current position of the magnetic field sensor 101 in the magnetic field satisfy formula (1).

[0113] Among them, V out is the output voltage of the operational amplifier module 410, VDD is the voltage value of the power supply terminal VDD, k is the amplification factor of the operational amplifier module 410, Vp is the output voltage of the first output terminal 101b1 of the magnetic field sensor 101, and Vn is the output voltage of the second output terminal 101b2 of the magnetic field sensor 101. offset is the bias voltage of the magnetic field sensor 101, I is the current value of the current flowing through the magnetic field sensor 101, B is the magnetic field strength in the detection direction of the current position of the magnetic field sensor 101 in the magnetic field, R H is the Hall coefficient of the magnetic field sensor 101 , and d is the thickness of the semiconductor magnetoelectric device (eg, Hall element) in the magnetic field sensor 101 along the magnetic field direction.

[0114] It can be understood that the voltage value of the power supply terminal VDD is -k times the bias voltage of the magnetic field sensor 101, so that the voltage value of the power supply terminal VDD is k*V offset can offset each other, reducing the bias voltage of the magnetic field sensor 101 on the input voltage and output voltage V of the operational amplifier module 410. out The effect caused by this is to increase the output voltage V of the operational amplifier module 410. out Accuracy in determining the distance between the lens 221 and the image sensor 201 .

[0115] In some examples, as shown in Figure 6, the output terminal 410b of the operational amplifier module 410 is electrically connected to the input terminal 430a of the digital processing module 430 (that is, the input terminal 430a of the digital processing module 430 is electrically connected to the output terminal 410b of the operational amplifier module 410), and the digital processing module 430 is used to: generate a control signal based on the output result of the operational amplifier module 410.

[0116] It is understood that the digital processing module 430 is used to implement digital processing and calculation functions. In some examples, the digital processing module 430 may include a CPU (full name: Central-Processing-Unit, Chinese name: Central Processing Unit), and in other examples, the digital processing module 430 may also include other processing chips.

[0117] The input terminal 430a of the digital processing module 430 is electrically connected to the output terminal 410b of the operational amplifier module 410, so that the digital processing module 430 can obtain the output voltage of the operational amplifier module 410, and determine the distance between the lens 221 and the image sensor 201 according to the output point voltage of the operational amplifier module 410 to generate a control signal, so that other components (such as the driving unit 211) can be controlled according to the control signal, so that the camera module 200 can achieve closed-loop autofocus.

[0118] 6 , the output end 430 b of the digital processing module 430 can be electrically connected to the driver 211. For example, the digital processing module 430 can include multiple output ports 430 b, a portion (one, two, or more) of the multiple output ports 430 b can be electrically connected to the driver 211, and another portion (one, two, or more) of the multiple output ports 430 b can be electrically connected to other control elements.

[0119] It can be understood that the output end 430b of the digital processing module 430 is electrically connected to the driving unit 211, so that the digital processing module 430 can control the driving unit 211 based on the control signal, so that the driving unit 211 can drive the lens 221 to move according to the current distance between the lens 221 and the image sensor 201, so that the camera module 200 can achieve closed-loop autofocus control, thereby improving the accuracy and reliability of the camera module 200 during autofocus.

[0120] In some examples, the detection unit 100 may further include a digital processing module 430 . In other examples, the camera module 200 may further include a digital processing module 430 .

[0121] When the detection unit 100 includes the digital processing module 430, the digital processing module 430 can be located on the first circuit board of the detection unit 100, and the digital processing module 430 can be electrically connected to the magnetic field sensor 101 via conductive traces. When the camera module 200 includes the digital processing module 430, the digital processing module 430 can be located on a circuit board other than the first circuit board of the detection unit 100, and can be electrically connected to the magnetic field sensor 101 via a structure such as a cable.

[0122] It can be understood that the detection unit 100 can be set to include a digital processing module 430, or the camera module 200 can be set to include a digital processing module 430, which can improve the setting flexibility of electronic devices in the camera module 200 (such as the digital processing module 430) and meet different usage requirements.

[0123] In some examples, at least two of the power supply 420, the operational amplifier module 410, and the digital processing module 430 may be located on the same circuit board (or within the same chip). When at least two of the power supply 420, the operational amplifier module 410, and the digital processing module 430 are located on the same circuit board (or within the same chip), the detection unit 100 may be located on the circuit board (or within the chip) or on another circuit board (or within the chip).

[0124] In other examples, the power supply 420, the operational amplifier module 410, and the digital processing module 430 may also be located on different circuit boards (or in different chips). The detection unit 100 may be located on the same circuit board (or in the same chip) as any one of the power supply 420, the operational amplifier module 410, and the digital processing module 430, or may be located on another circuit board (or in a chip).

[0125] In some examples, as shown in Figure 8, the camera module 200 may also include a switch 203, which is connected in series between the output terminal 410b of the operational amplifier module 410 and the input terminal 430a of the digital processing module 430, and is used to control the conduction or disconnection between the output terminal 410b of the operational amplifier module 410 and the input terminal 430a of the digital processing module 430.

[0126] FIG9 is a schematic diagram of a curve showing the magnetic field strength detected by the magnetic field sensor and changes with the distance between the lens and the image sensor provided in some embodiments of the present application.

[0127] The abscissa in Figure 9 represents the distance between the lens 221 and the image sensor 201, and the ordinate in Figure 9 represents the magnetic field strength detected by the magnetic field sensor 101. It will be understood that when the lens 221 moves along the first direction X, the distance between the lens 221 and the image sensor 201 will change. The magnet 222 is fixed relative to the lens 221, causing the distance between the magnet 222 and the image sensor 201 to change. The magnetic field sensor 101 is fixed relative to the image sensor 201, causing the relative position of the magnet 222 and the magnetic field sensor 101 to change. This causes the magnetic field strength in the detection direction at the current position of the magnetic field sensor 101 to change, and thus causes the magnetic field strength detected by the magnetic field sensor 101 to change.

[0128] As can be seen from Figure 9 , the distance between the lens 221 and the image sensor 201 and the magnetic field intensity detected by the magnetic field sensor 101 exhibit a relatively good linear correspondence only within a certain region. For example, this region can be referred to as the linear region (shown as region M1 in Figure 9 ). Outside the linear region, the linear relationship between the distance between the lens 221 and the image sensor 201 and the magnetic field intensity detected by the magnetic field sensor 101 is poor. Even outside the linear region, the same magnetic field intensity may correspond to multiple distances between the lens 221 and the image sensor 201, affecting the one-to-one correspondence between the two.

[0129] In order to ensure a one-to-one correspondence between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the magnetic field sensor 101, and thereby ensure a one-to-one correspondence between the distance between the lens 221 and the image sensor 201 and the output voltage of the magnetic field sensor 101, the lens 221 can only move within the range corresponding to the linear region.

[0130] Taking a mobile phone as an example, the camera module 200, as one of the core components of the mobile phone, places increasing demands on the focusing stroke (i.e., the movable range) of the lens 221. Therefore, it is necessary to increase the width of the linear region in the relationship curve between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the magnetic field sensor 101.

[0131] Figure 10 is a schematic diagram of the positional relationship between the lens, magnet, and magnetic field sensor provided in other embodiments of the present application. Figure 11 is a schematic diagram of a curve showing the magnetic field strength detected by the magnetic field sensor and how it varies with the distance between the lens and the image sensor provided in other embodiments of the present application. Figure 12 is a schematic diagram of the circuit topology of the camera module provided in still other embodiments of the present application.

[0132] In some implementations, as shown in FIG10 , the detection unit 100 may include at least two magnetic field sensors 101. For example, the detection unit 100 may include two, three, or more magnetic field sensors 101. The embodiments of the present application do not further limit the number of magnetic field sensors 101 included in the detection unit 100.

[0133] As shown in FIG10 , taking the detection unit 100 including three magnetic field sensors 101 as an example, the three magnetic field sensors 101 may include a first magnetic field sensor 1011, a second magnetic field sensor 1012, and a third magnetic field sensor 1013. The first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013 may be arranged on the housing 202 of the camera module 200 at intervals along the first direction X.

[0134] It can be understood that when the magnet 222 moves along the first direction X, the positions of the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013 in the magnetic field are different, resulting in different magnetic field intensities detected by the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013, and thus different output voltages of the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013. For example, the distance between the lens 221 and the image sensor 201 can be determined based on the output voltages of the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013.

[0135] As shown in FIG. 11 , the abscissa in FIG. 11 represents the distance between the lens 221 and the image sensor 201 , and the ordinate in FIG. 11 represents the magnetic field intensity detected by the magnetic field sensor 101 .

[0136] Curve a represents the correspondence between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the first magnetic field sensor 1011, curve b represents the correspondence between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the second magnetic field sensor 1012, curve c represents the correspondence between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the third magnetic field sensor 1013, and curve d represents the correspondence between the distance between the lens 221 and the image sensor 201 and the sum of the magnetic field strengths detected by the first magnetic field sensor 1011, the magnetic field strength detected by the second magnetic field sensor 1012, and the magnetic field strength detected by the third magnetic field sensor 1013.

[0137] For example, curve a, curve b, and curve c can be superimposed to obtain curve d. As can be seen from Figure 11, the trends of curves a, curve b, and curve c are substantially the same as the trend of curve e in Figure 9. In addition, after superimposing the magnetic field intensities detected by the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013, the linear region of curve d obtained (see the second region M2 in Figure 11) is wider than the linear region of curve e in Figure 9 (see the first region M1 in Figure 9).

[0138] Thus, it can be seen that providing at least two magnetic field sensors 101 to respectively detect the distance between the lens 221 and the image sensor 201 can increase the width of the linear region in the relationship curve between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the magnetic field sensor 101, thereby increasing the focusing range of the lens 221.

[0139] In some implementations, as shown in FIG12 , the number of operational amplifier modules 410 can be the same as the number of magnetic field sensors 101. For example, if there are three magnetic field sensors 101, the number of operational amplifier modules 410 can also be three. The three operational amplifier modules 410 can include a first operational amplifier module 4101, a second operational amplifier module 4102, and a third operational amplifier module 4103.

[0140] As shown in FIG12 , the input terminal 410a of the first operational amplifier module 4101 can be electrically connected to the output terminal 101b of the first magnetic field sensor 1011, so that the first operational amplifier module 4101 can amplify the output voltage of the first magnetic field sensor 1011. The input terminal 410a of the second operational amplifier module 4102 can be electrically connected to the output terminal 101b of the second magnetic field sensor 1012, so that the second operational amplifier module 4102 can amplify the output voltage of the second magnetic field sensor 1012. The input terminal 410a of the third operational amplifier module 4103 can be electrically connected to the output terminal 101b of the third magnetic field sensor 1013, so that the third operational amplifier module 4103 can amplify the output voltage of the third magnetic field sensor 1013.

[0141] As shown in Figure 12, the input terminal 430a of the digital processing module 430 can be electrically connected to the output terminal 410b of the first operational amplifier module 4101, the output terminal 410b of the second operational amplifier module 4102, and the output terminal 410b of the third operational amplifier module 4103, so that the digital processing module 430 can obtain the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103.

[0142] In some examples, as shown in FIG12 , the switch 203 may include a first switch 2031, a second switch 2032, and a third switch 2033. The first switch 2031 is connected in series between the output terminal 410b of the first operational amplifier module 4101 and the input terminal 430a of the digital processing module 430 to control the conduction or disconnection between the output terminal 410b of the first operational amplifier module 4101 and the input terminal 430a of the digital processing module 430. The second switch 2032 is connected in series between the output terminal 410b of the second operational amplifier module 4102 and the input terminal 430a of the digital processing module 430 to control the conduction or disconnection between the output terminal 410b of the second operational amplifier module 4102 and the input terminal 430a of the digital processing module 430. The third switch 2033 is connected in series between the output terminal 410b of the third operational amplifier module 4103 and the input terminal 430a of the digital processing module 430 to control the conduction or disconnection between the output terminal 410b of the third operational amplifier module 4103 and the input terminal 430a of the digital processing module 430.

[0143] The digital processing module 430 can respectively obtain the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103. In some examples, within a unit acquisition time period (e.g., within 1 second), the first switch 2031 can be controlled to be closed, so that the digital processing module 430 can obtain the output voltage of the first operational amplifier module 4101. Thereafter, the first switch 2031 can be controlled to be opened, and the second switch 2032 can be controlled to be closed, so that the digital processing module 430 can obtain the output voltage of the second operational amplifier module 4102. Thereafter, the second switch 2032 can be controlled to be opened, and the third switch 2033 can be controlled to be closed, so that the digital processing module 430 can obtain the output voltage of the third operational amplifier module 4103. In other examples, the first switch 2031, the second switch 2032, and the third switch 2033 can also be closed and opened in other orders.

[0144] In some examples, the digital processing module 430 can calculate the sum of the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103 to determine the distance between the lens 221 and the image sensor 201 through the sum of the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103.

[0145] In other examples, the digital processing module 430 can calculate the average of the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103 to determine the distance between the lens 221 and the image sensor 201 based on the average of the output voltages of the first operational amplifier module 4101, the second operational amplifier module 4102, and the third operational amplifier module 4103.

[0146] That is, in the above implementation, it is necessary to set up multiple operational amplifier modules 410 and electrically connect them to multiple magnetic field sensors 101 in a one-to-one correspondence, and it is necessary for the digital processing module 430 to digitally calculate (sum or average) the output voltages of the multiple operational amplifier modules 410 to obtain the distance between the lens 221 and the image sensor 201.

[0147] The inventors of this application have discovered that the above implementation method has at least the following technical problems:

[0148] Providing multiple operational amplifier modules 410 electrically connected to multiple magnetic field sensors 101 in a one-to-one correspondence increases the number of operational amplifier modules 410 in the camera module 200, increases the area occupied by the operational amplifier modules 410 on the circuit board (or in the chip), and also leads to an increase in the cost of the camera module 200.

[0149] In addition, the digital processing module 430 needs to sum or average the output voltages of multiple operational amplifier modules 410, which takes a long time and increases the time required for closed-loop autofocus of the camera module 200, affecting the performance of the camera module 200.

[0150] Figure 13 is a schematic diagram of the connection relationship of camera modules provided in some other embodiments of the present application. Figure 14 is a schematic diagram of the connection relationship of camera modules provided in some other embodiments of the present application. Figure 15 is a schematic diagram of the circuit topology of camera modules provided in some other embodiments of the present application.

[0151] Based on this, embodiments of the present application provide a detection unit 100. It is understood that the detection unit 100 is used to detect the distance between the lens 221 and the image sensor 201. The detection unit 100 includes at least two magnetic field sensors 101. It is understood that the at least two magnetic field sensors 101 can be of the same or different types. In some examples, both of the at least two magnetic field sensors 101 can be Hall sensors.

[0152] For example, as shown in FIG13 , the at least two magnetic field sensors 101 may include a first magnetic field sensor 1011 , a second magnetic field sensor 1012 , . . . an nth magnetic field sensor 101n (n is a positive integer greater than or equal to 3).

[0153] 13 , at least two magnetic field sensors 101 are connected in parallel. Output terminals 101 b of the at least two magnetic field sensors 101 are electrically connected to form a connection node P, to which the input terminal 410 a of the operational amplifier module 410 is electrically connected.

[0154] As can be understood, as shown in FIG13 , connection node P is not a physical component but rather represents the junction of related electrical connections in the circuit topology diagram. In other words, connection node P is equivalent to the junction point formed by electrically connecting the output terminals 101b of at least two magnetic field sensors 101. The output terminals 101b of at least two magnetic field sensors 101 are electrically connected to form connection node P such that the voltage value at connection node P is equal to the average of the output voltages of the at least two magnetic field sensors 101.

[0155] In an embodiment of the present application, at least two magnetic field sensors 101 are provided. The at least two magnetic field sensors 101 are capable of respectively detecting the magnetic field strength in the detection direction at their current position in the magnetic field, and converting the detected magnetic field strength into a corresponding voltage signal. This increases the width of the linear region in the relationship curve between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the magnetic field sensor 101, thereby increasing the focusing range of the lens 221.

[0156] Furthermore, the output terminals 101b of at least two magnetic field sensors 101 are electrically connected to form a connection node P, and the voltage value of the connection node P can be equal to the average value of the output voltages of the at least two magnetic field sensors 101. The input terminal 410a of the operational amplifier module 410 is electrically connected to the connection node P, so that the operational amplifier module 410 can obtain the average value of the output voltages of the at least two magnetic field sensors 101 through the connection node P and amplify the average value of the output voltages of the at least two magnetic field sensors 101. This eliminates the need to provide multiple operational amplifier modules 410 for one-to-one electrical connection with multiple magnetic field sensors 101, thereby reducing the number of operational amplifier modules 410, lowering the cost of the camera module 200, and reducing the area occupied by the operational amplifier modules 410 on the circuit board (or within the chip).

[0157] In addition, the output ends of at least two magnetic field sensors 101 are electrically connected to form a connection node P, and the output voltages of the at least two magnetic field sensors 101 are averaged through a hardware circuit, so that the digital processing module 430 does not need to perform digital calculations (such as summing or averaging) on ​​the output voltages of the at least two magnetic field sensors 101, thereby saving the computing power of the digital processing module 430, reducing the delay of the digital processing module 430, and reducing the time required to obtain the average value of the output voltages of the at least two magnetic field sensors 101, thereby improving the response speed of the camera module 200 during closed-loop autofocus, thereby improving the efficiency of the camera module 200 during closed-loop autofocus.

[0158] That is, by adopting the above configuration, the camera module 200 can achieve low-cost, high-efficiency and long-distance (long focusing stroke) closed-loop autofocus.

[0159] For example, the detection unit 100 can be provided within a chip, in which case the connection node P can be a pin of the chip. Alternatively, the detection unit 100 can be provided on a circuit board (e.g., a first circuit board), in which case the output ends of at least two magnetic field sensors 101 can be electrically connected on the circuit board to form a connection node. The output ends of at least two magnetic field sensors 101 can also form a connection node via a peripheral circuit electrically connected to the circuit board.

[0160] In some examples, as shown in FIG14 and FIG15 , the magnetic field sensor 101 has a first output terminal 101 b 1 and a second output terminal 101 b 2 , and the first output terminals 101 b 1 of at least two magnetic field sensors 101 are electrically connected to form a first connection node P 1 . The second output terminals 101 b 2 of at least two magnetic field sensors 101 are electrically connected to form a second connection node P 2 .

[0161] It can be understood that the first output terminals 101b1 of the at least two magnetic field sensors 101 are electrically connected to form a first connection node P1, so that the voltage value of the first connection node P1 can be the average of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101. The second output terminals 101b of the at least two magnetic field sensors 101 are electrically connected to form a second connection node P2, so that the voltage value of the second connection node P2 can be the average of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101.

[0162] For example, as shown in Figures 14 and 15, the input terminal 410a of the operational amplifier module 410 can be electrically connected to the first connection node P1 and the second connection node P2, so that the operational amplifier module 410 can obtain the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101. The operational amplifier module 410 can perform a difference processing between the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101 to obtain the average value of the output voltages of the at least two magnetic field sensors 101, and amplify the average value of the output voltages of the at least two magnetic field sensors 101.

[0163] The first output terminals 101b1 of at least two magnetic field sensors 101 are electrically connected to form a first connection node P1, and the second output terminals 101b2 of at least two magnetic field sensors 101 are electrically connected to form a second connection node P2, so that the voltage value of the first connection node P1 is equal to the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101, and the voltage value of the second connection node P2 is equal to the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101. The hardware circuit is used to calculate the average of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101, thereby saving the computing power of the digital processing module 430 and reducing the delay of the digital processing module 430, thereby reducing the time required for the camera module 200 to perform closed-loop autofocus and improving the efficiency of the camera module 200 during closed-loop autofocus.

[0164] In some examples, as shown in Figure 14, the first connection node P1 can be electrically connected to the first input terminal 410a1 of the operational amplifier module 410, and the second connection node P2 can be electrically connected to the second input terminal 410a2 of the operational amplifier module 410, so that the operational amplifier module 410 can obtain the voltage value of the first connection node P1 through the first input terminal 410a1 of the operational amplifier module 410, and obtain the voltage value of the second connection node P2 through the second input terminal 410a2 of the operational amplifier module 410.

[0165] Figure 16 is a schematic diagram illustrating the connection relationship of camera modules provided in further embodiments of the present application. Figure 17 is a schematic diagram illustrating the connection relationship of camera modules provided in further embodiments of the present application. Figure 18 is a schematic diagram illustrating the circuit topology of camera modules provided in further embodiments of the present application. Figure 19 is a schematic diagram illustrating the circuit topology of camera modules provided in further embodiments of the present application.

[0166] In some examples, as shown in FIG16 , the detection unit 100 further includes at least two current-limiting elements 102 . The first ends of the at least two current-limiting elements 102 are electrically connected to the output ends 101 b of the at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of the at least two current-limiting elements 102 are electrically connected to the connection node P. The current-limiting elements 102 are used to limit the current value of the current flowing between the output ends 101 b of any two magnetic field sensors 101.

[0167] For example, the current limiting element 102 may include a resistor, so that the current limiting element 102 can play a role in current limiting. In some examples, the current flowing through the current limiting element 102 can be ignored.

[0168] The number of current-limiting elements 102 can be equal to the number of magnetic field sensors 101, so that the first ends of at least two current-limiting elements 102 can be electrically connected to the output ends 101b of at least two magnetic field sensors 101 in a one-to-one correspondence. For example, as shown in FIG16 , the at least two current-limiting elements 102 can include a first current-limiting element 1021, a second current-limiting element 1022, ..., and an nth current-limiting element 102n.

[0169] The first end of the first current-limiting element 1021 can be electrically connected to the output terminal 101b of the first magnetic field sensor 1011. The first end of the second current-limiting element 1022 can be electrically connected to the output terminal 101b of the second magnetic field sensor 1022. ... The first end of the nth current-limiting element 102n can be electrically connected to the output terminal 101b of the nth magnetic field sensor 101n. The second ends of the first current-limiting element 1021, the second current-limiting element 1022, ..., the nth current-limiting element 102n are all electrically connected to the connection node P.

[0170] The first ends of at least two current-limiting elements 102 are electrically connected to the output ends 101b of at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of at least two current-limiting elements 102 are electrically connected to the connection node P, so that the current-limiting elements 102 can be connected in series between the output ends 101b of the magnetic field sensor 101 and the connection node P, thereby limiting the current value of the current flowing between the output ends 101b of the magnetic field sensor 101 and the connection node P, that is, limiting the current value of the current flowing between the output ends 101b of any two magnetic field sensors 101.

[0171] In this way, the risk of current flowing from the output end 101b of one magnetic field sensor 101 (for example, the first magnetic field sensor 1011) into the output end 101b of another magnetic field sensor 101 (magnetic field sensor 101 other than the first magnetic field sensor 1011) via the connection node P can be reduced, thereby reducing the impact on the output voltage of each magnetic field sensor 101 after the output ends 101b of at least two magnetic field sensors 101 are electrically connected to form the connection node P, so that the voltage value of the connection node P and the average value of the output voltages of at least two magnetic field sensors 101 when the at least two magnetic field sensors 101 are respectively electrically connected to at least two operational amplifier modules 410 can be roughly the same, thereby improving the reliability of the detection unit 100.

[0172] In some examples, the magnetic field sensor 101 and the current limiting element 102 are electrically connected via conductive traces on a circuit board of the detection unit 100 .

[0173] Such an arrangement enables the magnetic field sensor 101 and the current limiting element 102 to be located on the same circuit board (i.e., the first circuit board), and electrical connection is achieved through the conductive traces on the first circuit board, thereby reducing the distance between the magnetic field sensor 101 and the current limiting element 102, which is conducive to the miniaturization of the detection unit 100.

[0174] In some examples, as shown in Figures 17 and 18, the current-limiting element 102 may include a first sub-element 103 and a second sub-element 104. The first ends of at least two first sub-element 103 are electrically connected to the first output terminals 101b1 of at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of at least two first sub-element 103 are electrically connected to the first connection node P1. The first ends of at least two second sub-element 104 are electrically connected to the second output terminals 101b2 of at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of at least two second sub-element 104 are electrically connected to the second connection node P2.

[0175] In some examples, the number of first sub-elements 103, second sub-elements 104, and magnetic field sensors 101 is the same. The resistance values ​​of the first sub-elements 103 and the second sub-elements 104 can be equal or different. The resistance values ​​of different first sub-elements 103 electrically connected to different magnetic field sensors 101 can be equal or different. The resistance values ​​of different second sub-elements 104 electrically connected to different magnetic field sensors 102 can be equal or different.

[0176] As shown in FIG17 , the first ends of at least two first sub-elements 103 are electrically connected to the first output ends 101b1 of at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of at least two first sub-elements 103 are electrically connected to the first connection node P1. This allows the first sub-elements 103 to be connected in series between the first output ends 101b1 of the magnetic field sensors 101 and the first connection node P1, thereby limiting the current flowing between the first output ends 101b1 of the magnetic field sensors 101 and the first connection node P1. This reduces the risk of current flowing from the first output end 101b1 of one magnetic field sensor 101 (e.g., the first magnetic field sensor 1011) through the first connection node P1 into the first output end 101b1 of another magnetic field sensor 101 (a magnetic field sensor 101 other than the first magnetic field sensor 1011). This reduces the impact of the electrical connection of the first output ends 101b1 of the at least two magnetic field sensors 101 to form the connection node P on the output voltage of the first output end 101b1 of each magnetic field sensor 101, thereby improving the reliability of the detection unit 100.

[0177] As shown in FIG17 , the first ends of at least two second sub-elements 104 are electrically connected to the second output ends 101b2 of at least two magnetic field sensors 101 in a one-to-one correspondence, and the second ends of the at least two second sub-elements 104 are electrically connected to the second connection node P2, so that the second sub-elements 104 can be connected in series between the second output end 101b2 of the magnetic field sensor 101 and the second connection node P2, thereby limiting the current value flowing between the second output end 101b2 of the magnetic field sensor 101 and the second connection node P2, thereby reducing the risk of current flowing from the second output end 101b2 of one magnetic field sensor 101 (for example, the first magnetic field sensor 1011) through the second connection node P2 to the second output end 101b2 of another magnetic field sensor 101 (a magnetic field sensor 101 other than the first magnetic field sensor 1011). This reduces the impact of the second output end 101b2 of the at least two magnetic field sensors 101 electrically connected to form the connection node P on the output voltage of the second output end 101b2 of each magnetic field sensor 101, thereby improving the reliability of the detection unit 100.

[0178] In some examples, as shown in FIG18 , the first sub-element 103 includes a first resistor R1, and the second sub-element 104 includes a second resistor R2. The resistance of the first resistor R1 is equal to the resistance of the second resistor R2. In other examples, the first sub-element 103 includes multiple first resistors R1, which are electrically connected. The second sub-element 104 includes multiple second resistors R2, which are electrically connected. The resistance of the multiple first resistors R1 after being electrically connected is equal to the resistance of the multiple second resistors R2 after being electrically connected.

[0179] For example, the electrical connection method of the plurality of first resistors R1 may include at least one of series connection and parallel connection, and the electrical connection method of the plurality of second resistors R2 may include at least one of series connection and parallel connection. The electrical connection method of the plurality of first resistors R1 and the electrical connection method of the plurality of second resistors R2 may be the same or different.

[0180] The first sub-element 103 includes a first resistor R1, and the second sub-element 104 includes a second resistor R2, so that the first sub-element 103 and the second sub-element 104 can function as current limiters. Furthermore, the resistance of the first resistor R1 is equal to the resistance of the second resistor R2, or the resistance of multiple first resistors R1 electrically connected is equal to the resistance of multiple second resistors R2 electrically connected. This simplifies the calculation process for the amplification factor of the operational amplifier module 410 and improves the ease of use of the detection unit 100.

[0181] In the embodiment of the present application, an example is given in which the first sub-element 103 includes a first resistor R1 and the second sub-element 104 includes a second resistor R2 .

[0182] In some examples, the resistance of the first resistor R1 and the resistance of the second resistor R2 are equal and much larger than the output internal resistance of the magnetic field sensor 101. As the magnetic field strength in the detection direction of the magnetic field sensor 101 changes, the output internal resistance of the magnetic field sensor 101 will change. For example, the resistance of the first resistor R1 and the second resistor R2 can be 20 times, 30 times, 40 times, 50 times or 60 times the output internal resistance of the magnetic field sensor 101 (for example, the maximum value, minimum value or average value of the output internal resistance of the magnetic field sensor 101). It can be understood that the embodiments of the present application do not further limit the resistance of the first resistor R1 and the second resistor R2.

[0183] In other examples, the resistance values ​​of the first resistor R1 and the second resistor R2 may be different. The resistance values ​​of different first resistors R1 electrically connected to different magnetic field sensors 101 may be equal or different. The resistance values ​​of different second resistors R2 electrically connected to different magnetic field sensors 102 may be equal or different.

[0184] In some examples, as shown in Figures 18 and 19, the operational amplifier module 410 includes a differential amplifier circuit. The differential amplifier circuit is configured to obtain an average voltage value of the first output terminals 101b1 of at least two magnetic field sensors 101 and an average voltage value of the second output terminals 101b2 of at least two magnetic field sensors 101. The operational amplifier module 410 calculates the difference between the average voltage value of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average voltage value of the second output terminals 101b2 of the at least two magnetic field sensors 101 to obtain an average value of the output voltages of the at least two magnetic field sensors 101. The operational amplifier module 410 then amplifies the average value of the output voltages of the at least two magnetic field sensors 101.

[0185] It can be understood that the differential amplifier circuit can amplify and output the average value of the output voltages of at least two magnetic field sensors 101 (the output voltage of the magnetic field sensor 101 is the difference between the voltage value of the first output terminal 101b1 of the magnetic field sensor 101 and the voltage value of the second output terminal 101b2 of the magnetic field sensor 101), thereby improving the accuracy of determining the distance between the lens 221 and the image sensor 201 based on the output voltage of the operational amplifier module 410.

[0186] The structure of the differential amplifier circuit is illustrated below by taking the differential amplifier circuit as a typical negative feedback amplifier as an example.

[0187] In some examples, as shown in FIG18 and FIG19 , the differential amplifier circuit may include an operational amplifier OP, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4. The resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6.

[0188] A first end of the third resistor R3 is electrically connected to the non-inverting input terminal OP1 of the operational amplifier OP, and a second end of the third resistor R3 is electrically connected to the first connection node P1. A first end of the fourth resistor R4 is electrically connected to the inverting input terminal OP2 of the operational amplifier OP, and a second end of the fourth resistor R4 is electrically connected to the second connection node P2. A first end of the fifth resistor R5 is electrically connected to the non-inverting input terminal OP1 of the operational amplifier OP, and a second end of the fifth resistor R5 is electrically connected to the power supply terminal VDD (see FIG. 18 ) or the ground terminal GND (see FIG. 19 ). A first end of the sixth resistor R6 is electrically connected to the inverting input terminal OP2 of the operational amplifier OP, and a second end of the sixth resistor R6 is electrically connected to the output terminal OP3 of the operational amplifier OP.

[0189] It can be understood that the non-inverting input terminal OP1 of the operational amplifier OP can be the first input terminal 410a1 of the operational amplifier module 410, the inverting input terminal OP2 of the operational amplifier OP can be the second input terminal 410a2 of the operational amplifier module 410, and the output terminal OP3 of the operational amplifier OP can be the output terminal 410b of the operational amplifier module 410.

[0190] It is understandable that the differential amplifier circuit may also be a negative feedback amplifier circuit of other structures. The embodiments of the present application do not further limit the structure of the differential amplifier circuit.

[0191] In some examples, the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4. For example, the resistance of the third resistor R3 and the resistance of the fourth resistor R4 can be a first resistance. The resistance of the fifth resistor R5 and the resistance of the sixth resistor R6 are equal to each other. For example, the resistance of the fifth resistor R5 and the resistance of the sixth resistor R6 can be a second resistance. In some examples, the second resistance is greater than the first resistance.

[0192] It can be understood that the second end of the fifth resistor R5 is electrically connected to the power supply terminal VDD or the ground terminal GND, so that the current flowing out of the first output terminal 101b1 of at least two magnetic field sensors 101 can flow to the power supply terminal VDD or the ground terminal GND after passing through the third resistor R3 and the fifth resistor R5, thereby improving the setting flexibility of the circuit structure of the camera module 200.

[0193] It can be understood that the operational amplifier OP is capable of subtracting the voltage value of the non-inverting input terminal OP1 of the operational amplifier OP from the voltage value of the inverting input terminal OP2 of the operational amplifier OP. In this way, the non-inverting input terminal OP1 of the operational amplifier OP is electrically connected to the first connection node P1, and the inverting input terminal OP2 of the operational amplifier OP is electrically connected to the second connection node P2, so that the operational amplifier OP can obtain the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101, and subtract the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 from the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101.

[0194] It can be understood that the difference between the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101 is the average value of the output voltages of the at least two magnetic field sensors 101. After the operational amplifier OP obtains the average value of the output voltages of the at least two magnetic field sensors 101 by taking the difference between the average value of the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101, it can amplify and output the average value of the output voltages of the at least two magnetic field sensors 101, thereby improving the accuracy of determining the distance between the lens 221 and the image sensor 201 based on the output terminal OP3 of the operational amplifier OP (i.e., the output terminal 410b of the operational amplifier module 410).

[0195] The voltage at the connection point P will be demonstrated and explained in the following formula.

[0196] For example, as shown in FIG18 and FIG19 , the output voltage of the first output terminal 101b1 of the first magnetic field sensor 1011 is V p1 The output voltage of the second output terminal 101b2 of the first magnetic field sensor 1011 is V n1 The output voltage of the first output terminal 101b1 of the second magnetic field sensor 1012 is V p2 The output voltage of the second output terminal 101b2 of the second magnetic field sensor 1012 is V n2 , ... the output voltage of the first output terminal 101b1 of the nth magnetic field sensor 101n is V pn The output voltage of the second output terminal 101b2 of the nth magnetic field sensor 101n is V nn The voltage at the first end of the third resistor R3 (the end electrically connected to the non-inverting input terminal OP1 of the operational amplifier OP) is V + The voltage at the second end of the third resistor R3 is Vp (i.e., the voltage at the first connection point P1). The voltage at the first end of the fourth resistor R4 (the end electrically connected to the inverting input terminal OP2 of the operational amplifier OP) is V - , the voltage at the second end of the fourth resistor R4 is V n (ie, the voltage of the second connection node P2).

[0197] In order to simplify the calculation process, the resistance of the first resistor R1 and the resistance of the second resistor R2 are equal, and the resistance of multiple first resistors R1 and multiple second resistors R2 are equal. For example, the first resistor R1 and the second resistor R2 are both represented by R in express.

[0198] According to Kirchhoff's current law, the current flowing through the first connection node P1 satisfies formula (2).

[0199] According to Kirchhoff's current law, the current flowing through the second connection node P2 satisfies formula (3).

[0200] When the resistances of the third resistor R3 and the fourth resistor R4 are very large, the current flowing through the third resistor R3 is very small and negligible. In this case, the value on the right side of the equal sign in formula (2) is approximately zero. Similarly, the current flowing through the fourth resistor R4 is very small and negligible. The value on the right side of the equal sign in formula (3) is also approximately zero.

[0201] By transforming formula (2), we can get formula (2.1):

[0202] By transforming formula (3), we can get formula (3.1):

[0203] From formula (2.1), we can see that the voltage at the second end of the third resistor R3 is V p (ie, the voltage at the first connection node P1) is the average of the output voltages of the first output terminals 101b1 of at least two magnetic field sensors 101. As can be seen from formula (3.1), the voltage V at the second terminal of the fourth resistor R4 is n (ie, the voltage of the second connection node P2 ) is the average value of the output voltages of the second output terminals 101 b 2 of the at least two magnetic field sensors 101 .

[0204] That is, the first output terminals 101b1 of at least two magnetic field sensors 101 are electrically connected to form a first connection node P1, thereby averaging the output voltages of the first output terminals 101b1 of the at least two magnetic field sensors 101. The second output terminals 101b2 of at least two magnetic field sensors 101 are electrically connected to form a second connection node P2, thereby averaging the output voltages of the second output terminals 101b2 of the at least two magnetic field sensors 101.

[0205] In this way, the output voltages of at least two magnetic field sensors 101 are averaged through the hardware circuit, so that the digital processing module 430 does not need to perform digital calculations (such as summing or averaging) on ​​the output voltages of at least two magnetic field sensors 101, saving the computing power of the digital processing module 430 and reducing the delay of the digital processing module 430, thereby reducing the time required for the camera module 200 to perform closed-loop autofocus and improving the efficiency of the camera module 200 in closed-loop autofocus.

[0206] The amplification factor of the operational amplifier module 410 is demonstrated and explained below by means of a formula.

[0207] Referring again to FIG. 12 , when the magnetic field sensor 101 and the operational amplifier module 410 are electrically connected in a one-to-one correspondence, taking one magnetic field sensor 101 and the operational amplifier module 410 electrically connected thereto as an example (e.g., the first magnetic field sensor 1011 and the first operational amplifier module 4101), the second end of the fifth resistor R5 is electrically connected to the power supply terminal VDD. Since the operational amplifier OP has a "virtual off" characteristic in the negative feedback circuit, that is, the current flowing into the operational amplifier OP is approximately zero, according to Kirchhoff's current law, the current passing through the third resistor R3 and the fifth resistor R5 satisfies formula (4).

[0208] According to Kirchhoff's current law, the current passing through the fourth resistor R4 and the sixth resistor R6 satisfies formula (5).

[0209] In formula (4), VDD represents the voltage of the power supply terminal VDD. In formula (5), V out Represents the output voltage of the operational amplifier OP in the first operational amplifier module 4101. Since the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6, the fourth resistor R4 in formula (5) can be replaced by the third resistor R3, and the sixth resistor R6 in formula (5) can be replaced by the fifth resistor R5. It can be understood that the operational amplifier OP has a "virtual short" characteristic in the negative feedback circuit, that is, V + =V - For example, we can subtract formula (4) from formula (5) to get formula (6).

[0210] It can be seen from formula (6) that when the magnetic field sensor 101 and the operational amplifier module 410 are electrically connected in a one-to-one correspondence, the amplification factor of the operational amplifier module 410 is

[0211] As shown in FIG18 , when the output terminals of at least two magnetic field sensors 101 are electrically connected to form a connection node P, in order to simplify the calculation process, the resistance value of the first resistor R1 and the resistance value of the second resistor R2 are equal, and the resistance values ​​of the plurality of first resistors R1 and the plurality of second resistors R2 are equal, for example, the first resistor R1 and the second resistor R2 are both represented by R in express.

[0212] According to Kirchhoff's current law, the current flowing through the first connection node P1, the third resistor R3 and the fifth resistor R5 satisfies formula (7).

[0213] According to Kirchhoff's current law, the current flowing through the second connection node P2, the fourth resistor R4 and the sixth resistor R6 satisfies formula (8).

[0214] In formula (7), VDD represents the voltage of the power supply terminal VDD. In formula (8), V out Represents the output voltage of the operational amplifier OP. Since the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6, the fourth resistor R4 in formula (8) can be replaced by the third resistor R3, and the sixth resistor R6 in formula (8) can be replaced by the fifth resistor R5. It can be understood that the operational amplifier OP has a "virtual short" characteristic in the negative feedback circuit, that is, V + =V - For example, we can subtract formula (7) from formula (8) to get formula (9).

[0215] It can be seen from formula (9) that when the output terminals of at least two magnetic field sensors 101 are electrically connected to form a connection point P, and the first resistor R1 and the second resistor R2 are set to play a current limiting role, the first resistor R1 and the second resistor R2 (that is, the resistor R in ) participates in the amplification of the operational amplifier module 410, and the amplification factor of the operational amplifier module 410 is Compared to arranging a one-to-one electrical connection between the magnetic field sensor 101 and the operational amplifier module 410 , the amplification factor of the operational amplifier module 410 is reduced.

[0216] In some examples, the amplification factor of the operational amplifier module 410 can be increased by adjusting the resistance of the third resistor R3 and the resistance of the fifth resistor R5.

[0217] When the resistance values ​​of the first resistor R1 and the second resistor R2 electrically connected to the same magnetic field sensor 101 are equal, the resistance values ​​of the multiple first resistors R1 are different, and the resistance values ​​of the multiple second resistors R2 are different, the amplification factor of the operational amplifier module 410 is determined by the following derivation formula.

[0218] For example, the first resistor R1 electrically connected to the first output terminal 101b1 of the first magnetic field sensor 1011 can be represented by R in1 Since the resistance value of the second resistor R2 electrically connected to the second output terminal 101b2 of the first magnetic field sensor 1011 is equal to the resistance value of the first resistor R1 electrically connected to the first output terminal 101b1 of the first magnetic field sensor 1011, the second resistor R2 electrically connected to the second output terminal 101b2 of the first magnetic field sensor 1011 can also be expressed as Rin1 .

[0219] Similarly, the first resistor R1 electrically connected to the first output terminal 101b1 of the second magnetic field sensor 1012 can be expressed as R in2 The second resistor R2 electrically connected to the second output terminal 101b2 of the second magnetic field sensor 1012 can also be expressed as R in2 , ... The first resistor R1 electrically connected to the first output terminal 101b1 of the nth magnetic field sensor 101n can be expressed as R inn The second resistor R2 electrically connected to the second output terminal 101b2 of the nth magnetic field sensor 101n can also be expressed as R inn .

[0220] According to Kirchhoff's current law, the current flowing through the first connection node P1, the third resistor R3 and the fifth resistor R5 satisfies the following formula.

[0221] According to Kirchhoff's current law, the current flowing through the second connection node P2, the fourth resistor R4 and the sixth resistor R6 satisfies the following formula.

[0222] In formula (11), VDD represents the voltage of the power supply terminal VDD. In formula (13), V out represents the output voltage of the operational amplifier OP. Since the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6, the fourth resistor R4 in formula (12) and formula (13) can be replaced by the third resistor R3, and the sixth resistor R6 in (13) can be replaced by the fifth resistor R5.

[0223] Subtracting formula (12) from formula (10) yields formula (14).

[0224] By transforming formula (14), we can obtain formula (14.1).

[0225] It can be understood that the operational amplifier OP has a "virtual short" characteristic in the negative feedback circuit, that is, V + =V - Therefore, formula (14.1) can be simplified to obtain formula (14.2).

[0226] Subtracting formula (13) from formula (11) yields formula (15).

[0227] By transforming formula (15), we can obtain formula (15.1).

[0228] Substituting formula (15.1) into formula (14.2), we get V out The expression of (Formula (16)).

[0229] By transforming formula (16), we can obtain formula (16.1).

[0230] In formula (16.1), is the amplification factor of the operational amplifier module 410 , and the third resistor R3 and the fifth resistor R5 affect the amplification factor of the operational amplifier module 410 . is the average value of the output voltage of each magnetic field sensor 101, which is added before averaging. arrive Weight.

[0231] When the resistance values ​​of the first resistor R1 and the second resistor R2 electrically connected to the same magnetic field sensor 101 are unequal, the resistance values ​​of the plurality of first resistors R1 are unequal, and the resistance values ​​of the plurality of second resistors R2 are unequal, the amplification factor of the operational amplifier module 410 is determined by the following derivation formula.

[0232] For example, the first resistor R1 electrically connected to the first output terminal 101b1 of the first magnetic field sensor 1011 can be represented by R in11 The second resistor R2 electrically connected to the second output terminal 101b2 of the first magnetic field sensor 1011 can also be expressed as R in21 The first resistor R1 electrically connected to the first output terminal 101b1 of the second magnetic field sensor 1012 can be expressed as R in12 The second resistor R2 electrically connected to the second output terminal 101b2 of the second magnetic field sensor 1012 can also be expressed as R in22 , ... The first resistor R1 electrically connected to the first output terminal 101b1 of the nth magnetic field sensor 101n can be expressed as R in1n The second resistor R2 electrically connected to the second output terminal 101b2 of the nth magnetic field sensor 101n can also be expressed as R in2n .

[0233] According to Kirchhoff's current law, the current flowing through the first connection node P1, the third resistor R3 and the fifth resistor R5 satisfies the following formula.

[0234] According to Kirchhoff's current law, the current flowing through the second connection node P2, the fourth resistor R4 and the sixth resistor R6 satisfies the following formula.

[0235] Since the resistance of the third resistor R3 is equal to that of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to that of the sixth resistor R6, the fourth resistor R4 can be replaced by the third resistor R3, and the sixth resistor R6 can be replaced by the fifth resistor R5. In addition, because the denominators in formula (17) and formula (19) are different, the previous subtraction and then extraction of V cannot be used. p -V n The method of post-merge elimination is to directly calculate V p and V n .

[0236] Replace V in formula (17) p Combining them, we can get formula (17.1).

[0237] By transforming formula (18), we can obtain formula (18.1).

[0238] By transforming formula (18.1), we can obtain formula (18.11).

[0239] Substituting formula (18.11) into formula (17.1), we can obtain formula (21).

[0240] Formula (21) extracts V + Then we can get formula (21.1) and formula (21.2).

[0241] According to formula (21.1) and formula (21.2), formula (21.3) can be obtained.

[0242] Using the same method, the calculation formula of V- can be obtained, see formula (22).

[0243] It can be understood that the operational amplifier OP has a "virtual short" characteristic in the negative feedback circuit, that is, V + =V - Therefore, formula (21.3) and formula (22) are equal, and formula (23) can be obtained.

[0244] Simplify formula (23) and use a to express Use b to represent Formula (23.1) can be obtained.

[0245] According to formula (23.1), we can obtain formula (23.11) and formula (23.12).

[0246] From formula (23.12), it can be seen that the amplification factor of the operational amplifier module 410 is The voltage values ​​of the first output terminals 101b1 of at least two magnetic field sensors 101 and the voltage values ​​of the second output terminals 101b2 of at least two magnetic field sensors 101 are multiplied by different weights respectively, then subtracted to obtain differences, and finally the differences are averaged.

[0247] The weight of the first output terminal 101b1 of the i-th magnetic field sensor 101 is (i is a positive integer between 1 and n), the weight of the second output terminal 101b2 of the i-th magnetic field sensor 101 is (i is a positive integer between 1 and n).

[0248] In some examples, the resistance of the third resistor R3 and the resistance of the fourth resistor R4 are much greater than the output internal resistance of the magnetic field sensor 101 .

[0249] It is understandable that the resistance of the third resistor R3 and the fourth resistor R4 can be 20 times, 30 times, 40 times, 50 times, or 60 times, for example, the output internal resistance of the magnetic field sensor 101 (e.g., the maximum, minimum, or average output internal resistance of the magnetic field sensor 101). The resistance of the third resistor R3 and the fourth resistor R4 can be equal to or different from the resistance of the current-limiting element 102 (including the first sub-element 103 and the second sub-element 104).

[0250] Setting the resistance of the third resistor R3 and the fourth resistor R4 to be significantly greater than the output internal resistance of the magnetic field sensor 101 can reduce the impact of the output internal resistance of the magnetic field sensor 101 on the amplification factor of the operational amplifier module 410, thereby ensuring the accuracy of the amplification factor of the operational amplifier module 410. This eliminates the need to adjust the driver 110 based on the amplification factor of the operational amplifier module 410, thereby improving the ease of use of the detection unit 100.

[0251] In some examples, the resistance of the third resistor R3 and the fourth resistor R4 is a first resistance, the resistance of the fifth resistor R5 and the sixth resistor R6 is a second resistance, and the second resistance is m times the first resistance, where m is a positive number and greater than 1.

[0252] The second resistance value is set to m times the first resistance value, where m is a positive number and greater than 1, so that the operational amplifier module 410 can amplify the difference between the voltage value of the non-inverting input terminal OP1 of the operational amplifier OP and the voltage value of the inverting input terminal OP2 of the operational amplifier OP. In other words, the operational amplifier module 410 can amplify the difference between the average value of the output voltage of the first output terminal 101b1 of the at least two magnetic field sensors 101 and the average value of the output voltage of the second output terminal 101b2 of the at least two magnetic field sensors 101, thereby increasing the output voltage of the operational amplifier module 410 and thereby improving the accuracy of determining the distance between the lens 221 and the image sensor 201 based on the output voltage of the operational amplifier module 410.

[0253] It is understandable that when the detection unit 100 does not include the current-limiting element 102, or when the resistance of the current-limiting element 102 is small and negligible, the ratio m of the second resistance to the first resistance is equal to the amplification factor k of the operational amplifier module 410. When the resistance of the current-limiting element 102 is large and non-negligible, the current-limiting element 102 participates in the amplification of the operational amplifier module 410, and the ratio m of the second resistance to the first resistance is greater than the amplification factor k of the operational amplifier module 410.

[0254] In some examples, the differential amplifier circuit is electrically connected to the power supply terminal VDD. For example, as shown in FIG18 , when the differential amplifier circuit includes a typical negative feedback amplifier circuit, the second end of the fifth resistor R5 is electrically connected to the power supply terminal VDD. The voltage value of the power supply terminal VDD is -k times the average value of the bias voltages of the at least two magnetic field sensors 101. Here, k is the amplification factor of the operational amplifier OP.

[0255] The voltage value of the power supply terminal VDD is set to -k times the average value of the bias voltages of the at least two magnetic field sensors 101, where k is the amplification factor of the operational amplifier module. This allows the power supply terminal VDD to compensate for the bias voltages of the at least two magnetic field sensors 101, thereby reducing the impact of the bias voltages of the at least two magnetic field sensors 101 on the input voltage of the operational amplifier module 410 and the output voltage of the operational amplifier module 410 (that is, the output voltage of the operational amplifier OP), thereby improving the reliability of the camera module 200.

[0256] Figure 20 is a schematic diagram illustrating the connection relationship of camera modules provided in further embodiments of the present application. Figure 21 is a schematic diagram illustrating the connection relationship of camera modules provided in further embodiments of the present application. Figure 22 is a schematic diagram illustrating the circuit topology of camera modules provided in further embodiments of the present application. Figure 23 is a schematic diagram illustrating the circuit topology of camera modules provided in further embodiments of the present application. Figure 24 is a schematic diagram illustrating a curve showing how the magnetic field strength detected by the magnetic field sensor varies with the distance between the lens and the image sensor, provided in further embodiments of the present application.

[0257] As shown in Figures 20 and 21 , the magnetic field sensor 101 has a power input terminal 101a. In some examples, the resistance of at least two magnetic field sensors 101 is equal, and the power input terminals 101a of at least two magnetic field sensors 101 are electrically connected to the same power supply 420.

[0258] It is understood that the resistance of the magnetic field sensor 101 is the resistance between the power input terminal 101a of the magnetic field sensor 101 and the ground terminal GND of the magnetic field sensor 101. When the magnetic field strength in the detection direction changes at the current position of the magnetic field sensor 101 in the magnetic field, the resistance of the magnetic field sensor 101 changes slightly (essentially remains unchanged). In some examples, the difference between the resistance of the magnetic field sensor 101 and the rated resistance (predetermined resistance value) is less than or equal to 15%.

[0259] When the resistances of at least two magnetic field sensors 101 are equal, the resistances of at least two magnetic field sensors 101 can be completely equal or approximately equal. When the resistances of at least two magnetic field sensors 101 are equal, as shown in Figures 22 and 23 , at least two magnetic field sensors 101 can be electrically connected to the same power supply 420, so that one power supply 420 can power at least two magnetic field sensors 101, thereby reducing the number of power supplies 420, reducing the area occupied by the power supply 420 on the circuit board (or within the chip), and reducing the cost of the camera module 200.

[0260] In other examples, as shown in FIG. 19 , the number of the power supplies 420 is at least two, and the power input terminals 101 a of the at least two magnetic field sensors 101 are electrically connected to the at least two power supplies 420 in a one-to-one correspondence.

[0261] As shown in FIG19 , the number of power supplies 420 can be the same as the number of magnetic field sensors 101. The first power supply 4201 can be electrically connected to the power input terminal 101a of the first magnetic field sensor 1011 to supply power to the first magnetic field sensor 1011. The second power supply 4202 can be electrically connected to the power input terminal 101a of the second magnetic field sensor 1012 to supply power to the second magnetic field sensor 1012. The nth power supply 420n can be electrically connected to the power input terminal 101a of the nth magnetic field sensor 101n to supply power to the nth magnetic field sensor 101n.

[0262] It can be understood that the number of power supplies 420 is set to at least two, and the power input terminals 101a of at least two magnetic field sensors 101 are electrically connected to at least two power supplies 420 in a one-to-one correspondence, so that one power supply 420 can power one magnetic field sensor 101, thereby reducing the mutual influence between at least two magnetic field sensors 101 and improving the reliability of the camera module 200.

[0263] As shown in Figures 21 and 22 , taking the example of at least two magnetic field sensors 101 whose power input terminals 101a are electrically connected to the same power supply 420, the current split by each magnetic field sensor 101 is inversely proportional to the resistance of the magnetic field sensor 101. In other words, the deviation in the current flowing through each magnetic field sensor 101 is due to the resistance deviation of each magnetic field sensor 101.

[0264] Ideally, the resistance of each magnetic field sensor 101 is the same, with the resistance ratio of each magnetic field sensor 101 being 1:1…:1. The ratio of the current flowing through each magnetic field sensor 101 is also 1:1…:1. However, in reality, the resistance of each magnetic field sensor 101 is not exactly the same, resulting in a non-ideal current split ratio for each magnetic field sensor 101. For example, the current split ratio of each magnetic field sensor 101 (i.e., the ratio of the current flowing through each magnetic field sensor 101) can be k1:k2…:kn.

[0265] Taking magnetic field sensor 101 as a Hall sensor as an example, see FIG5 . When the magnetic field strength in the detection direction at the current position of magnetic field sensor 101 in the magnetic field changes (i.e., when the magnetic field strength detected by magnetic field sensor 101 changes), the change in the resistance of first equivalent resistor Ra and the change in the resistance of third equivalent resistor Rb cancel each other out, and the change in the resistance of second equivalent resistor Rc and the change in the resistance of fourth equivalent resistor Rd cancel each other out, so that the resistance of magnetic field sensor 101 remains unchanged or approximately unchanged. For example, when the magnetic field strength detected by magnetic field sensor 101 changes, the change in the resistance of magnetic field sensor 101 is within 2%, and the change in the output voltage of magnetic field sensor 101 has an error within (the limit error of magnetic field sensor 101) 2%.

[0266] That is, when the magnetic field intensity detected by the magnetic field sensor 101 changes, the resistance of the magnetic field sensor 101 changes very little, thus having a negligible effect on the current flowing through the magnetic field sensor 101, allowing the magnetic field sensor 101 to operate in a constant current mode. In other words, when the magnetic field intensity detected by the magnetic field sensor 101 changes, the shunt ratio of each magnetic field sensor 101 is minimally affected. As a result, as the lens 221 moves along the first direction X, the shunt ratios of each magnetic field sensor 101 can remain constant at k1:k2…:kn.

[0267] As shown in Figures 22 and 23, taking the number of magnetic field sensors 101 as an example, the three magnetic field sensors 101 include a first magnetic field sensor 1011, a second magnetic field sensor 1012, and a third magnetic field sensor 1013. The number of current-limiting elements 102 may also be three, and the three current-limiting elements 102 may include a first current-limiting element 1021, a second current-limiting element 1022, and a third current-limiting element 1023. The first current-limiting element 1021 may be electrically connected to the first magnetic field sensor 1011, the second current-limiting element 1022 may be electrically connected to the second magnetic field sensor 1012, and the third current-limiting element 1023 may be electrically connected to the third magnetic field sensor 1013. There may be one power supply 420, which may be electrically connected to the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013 to supply power to the first magnetic field sensor 1011, the second magnetic field sensor 1012, and the third magnetic field sensor 1013.

[0268] The resistance error of the magnetic field sensor 101 is generally within ±15% of the rated resistance. For example, taking the case where the resistance errors of the three magnetic field sensors 101 are all 15% of the rated resistance, for example, the resistance of the first magnetic field sensor 1011 is 85% of the rated resistance, the resistance of the second magnetic field sensor 1012 is 85% of the rated resistance, and the resistance of the third magnetic field sensor 1013 is 115% of the rated resistance. The circuit of the camera module 200 is simulated, and the simulation results are shown in Figure 24.

[0269] As shown in FIG. 24 , the abscissa in FIG. 24 represents the distance between the lens 221 and the image sensor 201 , and the ordinate in FIG. 23 represents the magnetic field intensity detected by the magnetic field sensor 101 .

[0270] Curve f represents the corresponding relationship between the distance between the lens 221 and the image sensor 201 and the magnetic field strength obtained by superimposing the magnetic field strengths detected by the three magnetic field sensors 101, when the three power supplies 420 are electrically connected to the three magnetic field sensors 101, respectively, and the magnetic field sensors 101 are electrically connected to the three operational amplifier modules 410, respectively. Curve g represents the corresponding relationship between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the three magnetic field sensors 101, when the power supplies 420 are electrically connected to the three magnetic field sensors 101, the output terminals of the three magnetic field sensors 101 are electrically connected to form a connection node P, and the input terminal 410a of the operational amplifier module 410 is electrically connected to the connection node P.

[0271] As can be seen from Figure 24, both curves f and g are linear. Because current-limiting element 102 is connected in series with magnetic field sensor 101 and connection node P, the amplification factor of operational amplifier module 410 decreases, resulting in a smaller amplitude variation in curve g. In some examples, the resistance values ​​of third resistor R3 and fifth resistor R5 can be adjusted to increase the amplification factor of operational amplifier module 410.

[0272] Because the resistance ratio of the three magnetic field sensors 101 is not strictly 1:1:1, the shunt ratio of the three magnetic field sensors 101 is not strictly 1:1:1, resulting in the linearity of curve g being lower than that of curve f. Fitting the points in the linear regions of curves f and g (as shown in region M3 in FIG. 24 ) reveals that the linearity of curve f is approximately 0.995, and the linearity of curve g is approximately 0.989. In some examples, laser calibration can be used to compensate for the linearity of curve g to improve the accuracy of camera module 200.

[0273] For example, the operating current of the magnetic field sensor 101 is 3 mA (unit: milliampere), the resistance values ​​of the first resistor R1 and the second resistor R2 are both 90 KΩ (unit: kilo-ohm), the resistance values ​​of the third resistor R3 and the fourth resistor R4 are both 30 KΩ, and the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 are both 90 KΩ.

[0274] For example, when three magnetic field sensors 101 are electrically connected to three operational amplifier modules 410 in a one-to-one correspondence, the amplification factor of the operational amplifier module 410 is 3 (90 kΩ / 30 kΩ), and the output voltage of each operational amplifier OP is 3 times Vp-Vn. In this case, the average value of the output voltages of the three operational amplifiers OP is shown in formula (24).

[0275] For example, when the output ends of the three magnetic field sensors 101 are electrically connected to form a connection node P, the input end of the operational amplifier module 410 is electrically connected to the connection node P, and the power supply 420 outputs a current of 9 mA to power the three magnetic field sensors 101, the output voltage of the operational amplifier is shown in formula (25).

[0276] It can be understood that in formula (11), V out is the output voltage of the operational amplifier OP, k1, k2 and k3 are the shunt ratios of the three magnetic field sensors 101, k1, k2 and k3 are constant, and the sum of k1, k2 and k3 is 3.

[0277] As can be seen from formulas (24) and (25), the current limiting element 102 participates in the amplification of the operational amplifier module 410, causing the amplification factor of the operational amplifier module 410 to change from 3 to 1.5. Due to the differences in the initial resistance of each magnetic field sensor 101, the output of each magnetic field sensor 101 accounts for a different proportion.

[0278] In summary, the embodiments of the present application have at least the following beneficial effects:

[0279] In an embodiment of the present application, at least two magnetic field sensors 101 are provided. The at least two magnetic field sensors 101 are capable of respectively detecting the magnetic field strength in the detection direction at their current position in the magnetic field, and converting the detected magnetic field strength into a corresponding voltage signal. This increases the width of the linear region in the relationship curve between the distance between the lens 221 and the image sensor 201 and the magnetic field strength detected by the magnetic field sensor 101, thereby increasing the focusing range of the lens 221.

[0280] Furthermore, the output terminals 101b of at least two magnetic field sensors 101 are electrically connected to form a connection node P, and the voltage value of the connection node P can be equal to the average value of the output voltages of the at least two magnetic field sensors 101. The input terminal 410a of the operational amplifier module 410 is electrically connected to the connection node P, so that the operational amplifier module 410 can obtain the average value of the output voltages of the at least two magnetic field sensors 101 through the connection node P and amplify the average value of the output voltages of the at least two magnetic field sensors 101. This eliminates the need to provide multiple operational amplifier modules 410 for one-to-one electrical connection with multiple magnetic field sensors 101, thereby reducing the number of operational amplifier modules 410, lowering the cost of the camera module 200, and reducing the area occupied by the operational amplifier modules 410 on the circuit board (or within the chip).

[0281] In addition, the output ends of at least two magnetic field sensors 101 are electrically connected to form a connection node P, and the output voltages of the at least two magnetic field sensors 101 are averaged through a hardware circuit, so that the digital processing module 430 does not need to perform digital calculations (such as summing or averaging) on ​​the output voltages of the at least two magnetic field sensors 101, thereby saving the computing power of the digital processing module 430, reducing the delay of the digital processing module 430, and reducing the time required to obtain the average value of the output voltages of the at least two magnetic field sensors 101, thereby improving the response speed of the camera module 200 during closed-loop autofocus, thereby improving the efficiency of the camera module 200 during closed-loop autofocus.

[0282] That is, by adopting the above configuration, the camera module 200 can achieve low-cost, high-efficiency and long-distance (long focusing stroke) closed-loop autofocus.

[0283] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in this application should be included within the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A detection unit, characterized in that: include: At least two magnetic field sensors, the at least two magnetic field sensors are connected in parallel; The output ends of the at least two magnetic field sensors are electrically connected to form a connection node, and the input end of the operational amplifier module is electrically connected to the connection node.

2. The detection unit according to claim 1, characterized in that: The magnetic field sensor has a first output terminal and a second output terminal. The first output terminals of the at least two magnetic field sensors are electrically connected to form a first connection node. The second output terminals of the at least two magnetic field sensors are electrically connected to form a second connection node.

3. The detection unit according to claim 2, characterized in that: Also includes: At least two current limiting elements; the first ends of the at least two current limiting elements are electrically connected to the output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of the at least two current limiting elements are electrically connected to the connection node; the current limiting elements are used to limit the current value of the current flowing between any two output ends of the magnetic field sensors.

4. The detection unit according to claim 3, characterized in that: The current limiting element includes a first sub-element and a second sub-element; The first ends of at least two of the first sub-elements are electrically connected to the first output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of at least two of the first sub-elements are electrically connected to the first connection node; The first ends of at least two of the second sub-elements are electrically connected to the second output ends of the at least two magnetic field sensors in a one-to-one correspondence, and the second ends of at least two of the second sub-elements are electrically connected to the second connection node.

5. The detection unit according to claim 4, characterized in that: The first sub-element includes a first resistor, and the second sub-element includes a second resistor; the resistance value of the first resistor is equal to the resistance value of the second resistor; or, The first sub-element includes a plurality of first resistors, which are electrically connected; the second sub-element includes a plurality of second resistors, which are electrically connected; the resistance value of the plurality of first resistors after being electrically connected is equal to the resistance value of the plurality of second resistors after being electrically connected.

6. The detection unit according to any one of claims 3 to 5, characterized in that: The operational amplifier module includes a differential amplifier circuit; The differential amplifier circuit is configured as follows: Acquire an average voltage value of the first output ends of the at least two magnetic field sensors and an average voltage value of the second output ends of the at least two magnetic field sensors; Calculating a difference between an average voltage value of the first output terminals of the at least two magnetic field sensors and an average voltage value of the second output terminals of the at least two magnetic field sensors to obtain an average value of the output voltages of the at least two magnetic field sensors; An average value of the output voltages of the at least two magnetic field sensors is amplified.

7. The detection unit according to claim 6, characterized in that: The differential amplifier circuit is electrically connected to a power supply terminal; a voltage value of the power supply terminal is -k times the average value of the bias voltages of the at least two magnetic field sensors; wherein k is the gain factor of the operational amplifier module.

8. The detection unit according to any one of claims 3 to 7, characterized in that: Also includes: A first circuit board, wherein the first circuit board comprises a conductive trace; the magnetic field sensor and the current limiting element are electrically connected via the conductive trace.

9. The detection unit according to any one of claims 1 to 8, characterized in that: The resistances of the at least two magnetic field sensors are equal, and the power input terminals of the at least two magnetic field sensors are electrically connected to the same power supply; or, The number of the power supplies is at least two, and the power input terminals of the at least two magnetic field sensors are electrically connected to the at least two power supplies in a one-to-one correspondence.

10. The detection unit according to any one of claims 1 to 9, characterized in that: The output end of the operational amplifier module is electrically connected to the input end of the digital processing module; the digital processing module is used to generate a control signal based on the output result of the operational amplifier module.

11. A camera module, characterized in that: include: Lens; Image sensor; The detection unit according to any one of claims 1 to 10; The detection unit is used to detect the distance between the lens and the image sensor.

12. The camera module according to claim 11, characterized in that: The detection unit includes the operational amplifier module, and the input end of the operational amplifier module is electrically connected to the connection node; or, The camera module also includes the operational amplifier module, and the input end of the operational amplifier module is electrically connected to the connection node.

13. The camera module according to claim 11 or 12, characterized in that: The detection unit further includes a power supply, and the power supply is electrically connected to a power input terminal of the magnetic field sensor; or, The camera module also includes a power supply, which is electrically connected to a power input terminal of the magnetic field sensor.

14. The camera module according to any one of claims 11 to 13, characterized in that: It also includes a driving unit, which is used to drive the lens to move; The detection unit further includes a digital processing module, an input end of the digital processing module is electrically connected to an output end of the operational amplifier module, and an output end of the digital processing module is electrically connected to the driving unit; or, The camera module further includes a digital processing module, an input end of the digital processing module is electrically connected to an output end of the operational amplifier module, and an output end of the digital processing module is electrically connected to the driving unit.

15. An electronic device, characterized in that: include: case; The camera module according to any one of claims 11 to 14, wherein the camera module is located in the housing, and a portion of the camera module is exposed to the housing.

Images