Magnetic position sensor and anti-shake camera

Abstract

The utility model provides a magnetic position sensor and an anti-shake camera. The magnetic position sensor comprises a substrate; the signal processing circuit, the driving control circuit and the TMR magnetic sensor are formed on the basis of the substrate; and packaging. The TMR magnetic sensor can sense a magnetic field perpendicular to the surface of the substrate and transmit an obtained magnetic field sensing signal to the signal processing circuit, and the signal processing circuit is used for processing the magnetic field sensing signal to obtain a processed magnetic field sensing signal. The driving control circuit outputs a driving current according to the processed magnetic field sensing signal from the signal processing circuit, and the driving current enables the voice coil motor to drive the lens module to move, so that the compensation of the jitter of the lens module is realized, and the implementation cost of anti-jitter can be reduced at the same time.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of magnetic sensor, especially relates to a magnetic position sensor and anti-shake camera.

BACKGROUND

[0002] The requirement for the camera in mobile device is gradually improved, in order to reduce the image deterioration problem caused by camera shake, generally adds optical anti-shake module in lens module. The displacement produced in the shaking of lens module is detected by the combination of magnet and magnetic sensing chip. Specifically, the magnetic sensing chip is fixed, and the magnet moves with the shaking of lens module, and thus the magnetic field produced by the magnet at the position of magnetic sensing chip also changes, so that the magnetic sensing chip outputs the information related to the position of lens module and feeds back to the control system, and the control system outputs the driving current of corresponding size and direction to drive the voice coil motor to compensate the displacement caused by the shaking of lens module, thereby improving the image quality of lens.

[0003] At present, there are mainly two kinds of optical anti-shake schemes. The first kind adopts pure analog magnetic sensor plus driving control chip. The analog magnetic sensor generally adopts III-V group Hall sensor, and the optical anti-shake control precision of this scheme is very high due to the higher signal-to-noise ratio of III-V group Hall sensor compared with silicon-based Hall sensor, but the cost is also higher. Another scheme adopts silicon-based Hall sensor, and the driving control module is integrated together, compared with the first kind of scheme, the number of chips used is reduced, and the use cost is reduced. However, the control precision of this scheme is lower than that of the former. At the same time, the III-V group Hall sensor cannot be integrated on the silicon-based circuit, so the III-V group Hall sensor and the driving control module cannot be integrated together. Therefore, at present, there is a lack of a scheme which can maintain high precision control effect of optical anti-shake and low cost.

[0004] Therefore, it is urgent to propose a new technical scheme to solve the above problems.

UTILITARY MODEL CONTENT

[0005] One of the purposes of the utility model is to provide an improved magnetic position sensor and anti-shake camera, which can maintain high control precision and low cost scheme.

[0006] According to one aspect of the present invention, the present invention provides a magnetic position sensor, which includes: a substrate; a signal processing circuit, a drive control circuit and a TMR (Tunnel Magneto Resistance) magnetic sensor formed based on the substrate, the TMR magnetic sensor can sense a magnetic field perpendicular to the surface of the substrate and transmit the obtained magnetic field sensing signal to the signal processing circuit, the signal processing circuit is used to process the magnetic field sensing signal to obtain a processed magnetic field sensing signal, and the drive control circuit outputs a drive current according to the processed magnetic field sensing signal from the signal processing circuit; and packaging.

[0007] According to another aspect of the present invention, the present invention provides an anti-shake camera, which includes: a voice coil motor, which includes a moving part; a lens module mounted on the moving part of the voice coil motor, and the moving part of the voice coil motor can drive the lens module to move; a magnet fixed to the lens module; and a chip including the magnetic position sensor fixedly mounted on a substrate, with the chip and the magnet spaced apart and facing each other.

[0008] Compared to existing technologies, this invention integrates signal processing circuitry, drive control circuitry, and a TMR magnetic sensor into a single chip, reducing the number of chips and lowering costs. Furthermore, TMR magnetic sensors have a much higher signal-to-noise ratio than silicon-based Hall sensors. Therefore, anti-shake cameras using this magnetic position sensor have higher optical image stabilization control accuracy.

Brief Description of the Drawings

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. Among them:

[0010] Figure 1 Schematic diagram of the hierarchical structure of the magnetic position sensor in one embodiment of the present invention;

[0011] Figure 2 A top view schematic diagram of a TMR magnetic sensor arrangement in a magnetic position sensor chip in the present invention;

[0012] Figure 3 for Figure 2 A cross-sectional schematic diagram of a TMR magnetic sensor in a magnetic position sensor chip;

[0013] Figure 4Schematic top view of the first arrangement of two TMR magnetic sensors in the magnetic position sensor chip in the present invention;

[0014] Figure 5 Schematic top view of the second arrangement of two TMR magnetic sensors in the magnetic position sensor chip in the present invention;

[0015] Figure 6 A top view schematic diagram of the third arrangement of two TMR magnetic sensors in the magnetic position sensor chip of the present invention;

[0016] Figure 7 A top view schematic diagram of a positional arrangement of four TMR magnetic sensors in the magnetic position sensor chip of the present invention;

[0017] Figure 8 A top view schematic diagram of one arrangement of eight TMR magnetic sensors in a magnetic position sensor chip in the present invention;

[0018] Figure 9 This is a three-dimensional schematic diagram of the magnetic position sensor in the first application example of the present invention;

[0019] Figure 10 This is a side view schematic diagram of the magnetic position sensor in the first application example of the present invention;

[0020] Figure 11 This is a three-dimensional schematic diagram of the magnetic position sensor in the utility model in the second application example;

[0021] Figure 12 This is a side view schematic diagram of the magnetic position sensor in the second application example of the present invention;

[0022] Figure 13 The figure is a schematic diagram of the circuit structure of the magnetic position sensor in one embodiment of the present invention. [Specific implementation method]

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0024] The "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The "in one embodiment" that appears in different places in this specification does not all refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments. In the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", "coupled" and other terms indicating electrical connection should be understood in a broad sense; for example, it can be a direct electrical connection, or it can be indirectly electrically connected through an intermediate medium, and the intermediate medium can be an electronic component, a functional circuit, etc. For ordinary technicians in this field, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0025] This utility model provides an improved magnetic position sensor that integrates signal processing circuitry, drive control circuitry, and a TMR magnetic sensor into a single chip, reducing the number of chips and lowering costs. Furthermore, compared to silicon-based Hall sensors, TMR magnetic sensors have a higher signal-to-noise ratio. Therefore, anti-shake cameras using this magnetic position sensor have higher optical image stabilization control accuracy.

[0026] Figure 1 FIG. 1 is a schematic diagram of the hierarchical structure of the magnetic position sensor 100 in one embodiment of the present invention. Figure 13 FIG. 1 is a schematic diagram of the circuit structure of the magnetic position sensor 100 in one embodiment of the present invention.

[0027] like Figure 1 、 13 As shown, the magnetic position sensor 100 can be implemented as a chip, so in this utility model, the magnetic position sensor is sometimes referred to as a magnetic position sensor chip. Figure 1 and Figure 13 As shown, the magnetic position sensor 100 includes a substrate 110, a signal processing circuit 121 formed on the substrate 110, a drive control circuit 122, a TMR magnetic sensor 141, and a package 160. The package 160 can package the magnetic position sensor into a chip to protect the circuits within the chip.

[0028] The TMR magnetic sensor 141 is capable of sensing a magnetic field perpendicular to the surface of the substrate 110 (i.e., sensing a magnetic field along the z-axis in the figure) and transmitting the resulting magnetic field sensing signal to the signal processing circuit 121. The signal processing circuit 121 is configured to process the magnetic field sensing signal to obtain a processed magnetic field sensing signal. The drive control circuit 122 outputs a drive current based on the processed magnetic field sensing signal from the signal processing circuit.

[0029] like Figure 1 、13 As shown, the signal processing circuit 121 and the drive control circuit 122 are formed above the substrate 110. The signal processing circuit 121 and the drive control circuit 122 are located in the same layer, which is referred to as the circuit layer 120. The circuits in the circuit layer 120 can be manufactured using a CMOS (Complementary Metal Oxide Semiconductor) process, and therefore this circuit layer can also be referred to as a CMOS circuit layer. The signal processing circuit 121 and the drive control circuit 122 are electrically connected.

[0030] The TMR magnetic sensor 141 is formed above the circuit layer 120. The magnetic position sensor 100 further includes a first isolation via layer 130 formed between the circuit layer 120 and the layer where the TMR magnetic sensor 141 is located (which may be referred to as the sensor device layer 140), and one or more first via metals (not shown) formed in the first isolation via layer 130. The first via metals can electrically connect the TMR magnetic sensor 141 to the signal processing circuit 131 and can also connect the output of the drive control circuit 122 to the sensor device layer 140.

[0031] The magnetic position sensor 100 also includes a second isolation via layer 150 formed between the layer where the TMR magnetic sensor resides and the layer where the package 160 resides (which may be referred to as a packaging layer), and one or more second via metals (not shown) formed in the second isolation via layer 150. The first and second via metals and the layer 140 where the TMR magnetic sensor resides electrically connect the drive control circuit 122 to pins outside the package 160, allowing the drive control circuit 122 to output a drive current. The package 160 may be a wafer-level package, meaning that the wafer is directly packaged before being cut, rather than being cut into dies and then individually packaged.

[0032] It should be noted that the layer referred to in the present invention does not specifically refer to a specific thin film layer in the manufacturing process, but a collection of layers that have the ability to achieve defined functions.

[0033] like Figure 13As shown, the drive control circuit 122 includes a controller 1221, a memory 1222, and an output circuit 1223. The controller 1221 determines the current position of the lens module based on the magnetic field sensing signal from the signal processing circuit 121, determines the target position of the lens module based on predetermined parameters stored in the memory 1222, determines the required displacement of the lens module based on the current and target positions of the lens module, and outputs a current displacement control signal based on the required displacement of the lens module. The output circuit 1223 outputs a driving current to the coil of the voice coil motor based on the current displacement control signal. The moving part of the voice coil motor drives the lens module to move, so that the lens module ultimately moves to the target position. A magnet is mounted on the lens module, i.e., the magnet moves with the lens module. The movement of the lens module and the magnet causes a change in the z-axis magnetic field at the TMR magnetic sensor 141. That is, the movement of the magnet and the lens module can be measured by the change in the z-axis magnetic field at the TMR magnetic sensor 141.

[0034] In one embodiment, the magnetic position sensor 100 is fixed to a substrate, the magnet is fixed to a lens module, and the magnet moves with the lens module. The lens module is fixed to the moving portion of the voice coil motor. The drive control circuit 122 provides a drive current of appropriate direction and magnitude to the coil of the voice coil motor, thereby driving the moving portion of the voice coil motor to move the lens module to a target position, thereby achieving efficient and high-precision jitter displacement compensation.

[0035] Specifically, two magnetic position sensor chips are generally used, one chip is used for the x-axis displacement control of the lens module, and the other is used for the x-axis displacement control of the lens module, thereby realizing dual-axis displacement control and compensation of the lens module.

[0036] Specifically, the controller 1221 may be a PID controller, and the output circuit 1223 may be an H-Bridge circuit. The PID controller can achieve high-precision control.

[0037] Since the magnet itself generates magnetic fields with components in the x, y, and z directions, the TMR magnetic sensor 141 is insensitive to the magnetic field within the plane where the chip is located, that is, it is not sensitive to the magnetic fields of the x-axis and y-axis, but is only sensitive to the magnetic field of the z-axis, and the magnetic field within the plane does not affect the sensitivity and zero-field drift in the z-axis direction, where the plane formed by the x-axis and y-axis is parallel to the surface of the substrate, and the z-axis is perpendicular to the surface of the substrate. In addition, the TMR magnetic sensor 141 has a very high signal-to-noise ratio compared to the silicon-based Hall sensor, so the anti-shake camera using the magnetic position sensor has higher optical anti-shake control accuracy. In addition, the TMR magnetic sensor can be integrated on the circuit layer 120 and packaged into a chip using wafer-level packaging, which reduces the number of chips and reduces costs.

[0038] The number of TMR magnetic sensors in the magnetic position sensor may be one or more. Figure 2 and 3 As shown, the number of TMR magnetic sensors 220 in the magnetic position sensor chip (sometimes referred to simply as chip) 210 is one. Reference numerals 201 and 202 denote the center lines of the chip 210 along the x-axis and the y-axis, respectively. The TMR sensor 220 is located at the center of the chip 210, i.e., in the center region of both the x-axis and the y-axis. Figure 3 for Figure 2 A cross-sectional schematic diagram of a TMR magnetic sensor in a magnetic position sensor chip is shown, wherein 231 is a substrate, 232 is a circuit layer, 233 is a first isolation through-hole layer, 220 is a TMR magnetic sensor, 234 is a second isolation through-hole layer, and 235 is a packaging layer.

[0039] Figure 4 In FIG, there are two TMR magnetic sensors 311 and 312 in chip 310 (ie, magnetic position sensor chip), and 301 and 302 are the center lines of chip 310 along the y-axis and x-axis respectively. Figure 4 In FIG, the TMR magnetic sensors 311 and 312 are symmetrically distributed along the center lines 302 and 301 .

[0040] Figure 5 In FIG, there are two TMR magnetic sensors 321 and 322 in chip 320, and 303 is the center line of chip 330 along the x-axis (parallel to the x-axis). Figure 5 In FIG. 3 , the TMR magnetic sensors 321 and 322 are symmetrically distributed along the center line 303 , and the TMR magnetic sensors 321 and 322 are located on the left side of the chip 320 .

[0041] Figure 6 In FIG, there are two TMR magnetic sensors 331 and 332 in the chip 330, and 304 is the center line of the chip 330 along the x-axis. Figure 6In FIG. 3 , the TMR magnetic sensors 331 and 332 are symmetrically distributed along the center line 304 , and the TMR magnetic sensors 331 and 332 are located on the right side of the chip 330 .

[0042] Figure 7 In FIG. 3 , there are four TMR magnetic sensors 341, 342, 343, and 344 in chip 340. 305 and 306 are the center lines of chip 340 along the y-axis and z-axis. The four TMR magnetic sensors 341, 342, 343, and 344 are symmetrically distributed along center line 305 and symmetrically distributed along center line 306.

[0043] Figure 8 In FIG. 3 , there are eight TMR magnetic sensors 351 - 358 in chip 350 , with 308 and 307 being the center lines of chip 340 along the y-axis and x-axis. The eight TMR magnetic sensors 351 - 358 are symmetrically distributed along center line 308 and symmetrically distributed along center line 307 .

[0044] In the present invention, the number of TMR magnetic sensors may be greater than eight, with the upper limit being the area sufficient to cover the entire circuit layer plane. When the number of TMR magnetic sensors is greater than one, at least one TMR magnetic sensor is electrically connected to the signal processing circuit 121, and the remaining TMR magnetic sensors may or may not be connected to the signal processing circuit 121.

[0045] Figure 9 This is a three-dimensional schematic diagram of the magnetic position sensor in the first application example of the present invention; Figure 10 This is a side view schematic diagram of the magnetic position sensor in the utility model in the first application example.

[0046] like Figure 9 and 10As shown, the magnetic position sensor chip 402 is fixedly mounted on the substrate and cannot move. The magnet 401 is fixed on the lens module, and the lens module is mounted on the moving part of the voice coil motor. The moving part of the voice coil motor can drive the lens module to move, and the magnet 401 moves with the lens module. In this application example, the magnet 401 can move along the direction shown by 403 (i.e., the x-axis direction). The magnet has an N pole and an S pole arranged along the x-axis, that is, the magnet 401 is magnetized in a horizontal direction. The center line 404 of the magnet 401 parallel to the z-axis is perpendicular to the surface of the chip 402 and aligned with the center line of the magnetic position sensor chip 402 parallel to the z-axis. The arrow curve 405 indicates the magnetic flux lines of the magnetic field. When the magnet 401 moves to the left, the TMR magnetic sensor in the magnetic position sensor chip 402 senses the magnetic field in the negative direction of the Z axis. When the magnet 401 moves to the right, the TMR magnetic sensor in the magnetic position sensor chip 402 senses the magnetic field in the positive direction of the Z axis. The change in the magnitude of the magnetic field is approximately linear within a certain displacement range.

[0047] Figure 11 This is a three-dimensional schematic diagram of the magnetic position sensor in the utility model in the second application example; Figure 12 This is a side view schematic diagram of the magnetic position sensor in the second application example of the present invention.

[0048] like Figure 11 and 12 As shown, the magnetic position sensor chip 502 (or simply the chip, or it can be referred to as a chip including a magnetic position sensor) is fixedly mounted on the substrate and cannot move. The magnet 501 is fixed on the lens module, and the lens module is mounted on the moving part of the voice coil motor. The moving part of the voice coil motor can drive the lens module to move, and the magnet 501 moves with the lens module. In this application example, the magnet 501 can move along the direction shown by 503 (i.e., the z-axis direction). The magnet has an N pole and an S pole arranged along the z-axis, that is, the magnet 501 is magnetized in the z-axis direction. The center line 504 of the magnet 501 parallel to the z-axis is perpendicular to the surface of the chip 502 and aligned with the center line of the magnetic position sensor chip 502 parallel to the z-axis. The arrow curve 505 indicates the magnetic flux lines of the magnetic field. When the magnet 501 moves upward, the TMR magnetic sensor in the magnetic position sensor chip 502 senses that the magnetic field in the Z-axis direction becomes smaller. When the magnet 501 moves downward, the TMR magnetic sensor in the magnetic position sensor chip 502 senses that the magnetic field in the Z-axis direction becomes larger. The change in the magnitude of the magnetic field is approximately linear within a certain displacement range.

[0049] According to another aspect of the present invention, a camera with an anti-shake function is provided, comprising: a voice coil motor (VCM) including a moving portion; a lens module mounted on the VCM's moving portion, the VCM's moving portion being capable of driving the lens module to move; a magnet fixed to the lens module; and a chip fixedly mounted on a substrate, comprising the magnetic position sensor disclosed in each of the above embodiments, the chip being spaced apart and opposed to the magnet. The chip senses a z-axis magnetic field and provides an output drive current to the VCM's coil, thereby controlling the moving portion to drive the lens module to move, thereby performing displacement control and compensation, thereby achieving anti-shake function.

[0050] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0051] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations of the present invention. Ordinary technicians in this field can change, modify and modify the above embodiments within the scope of the present invention.

Claims

1. A magnetic position sensor, characterized in that: It includes: substrate; A signal processing circuit, a drive control circuit, and a TMR magnetic sensor are formed based on the substrate, wherein the TMR magnetic sensor is capable of sensing a magnetic field perpendicular to the surface of the substrate and transmitting the obtained magnetic field sensing signal to the signal processing circuit, the signal processing circuit is used to process the magnetic field sensing signal to obtain a processed magnetic field sensing signal, and the drive control circuit outputs a drive current according to the processed magnetic field sensing signal from the signal processing circuit; and Encapsulation.

2. The magnetic position sensor according to claim 1, wherein The signal processing circuit and the drive control circuit are formed above the substrate, and the signal processing circuit and the drive control circuit are located in the same layer. The layer where the signal processing circuit and the drive control circuit are located is called a circuit layer. The signal processing circuit and the drive control circuit are electrically connected. The TMR magnetic sensor is formed above the circuit layer. The magnetic position sensor further includes a first isolation via layer formed between the circuit layer and the layer where the TMR magnetic sensor is located, and one or more first via metals formed in the first isolation via layer, wherein the first via metals electrically connect the TMR magnetic sensor and the signal processing circuit.

3. The magnetic position sensor according to claim 2, wherein: The magnetic position sensor further includes a second isolation via layer formed between the layer where the TMR magnetic sensor is located and the layer where the package is located, and one or more second via metals formed in the second isolation via layer. The driving control circuit is electrically connected to the pins outside the package through the first through-hole metal, the second through-hole metal and the layer where the TMR magnetic sensor is located.

4. The magnetic position sensor according to claim 1, wherein The number of the TMR magnetic sensors is one or more, The TMR magnetic sensors are symmetrically distributed along a center line of the magnetic position sensor that is parallel to the x-axis or the y-axis. The plane formed by the x-axis and the y-axis is parallel to the surface of the substrate, and the z-axis is perpendicular to the surface of the substrate.

5. The magnetic position sensor according to claim 1, wherein The drive control circuit includes a controller, a memory and an output circuit. The controller determines the current position of the lens module based on the magnetic field sensing signal from the signal processing circuit, determines the target position of the lens module based on the predetermined parameters in the memory, determines the displacement that the lens module needs to move based on the current position and target position of the lens module, and outputs a current displacement control signal based on the displacement that the lens module needs to move. The output circuit outputs a driving current to the coil of the voice coil motor based on the current displacement control signal, and the moving part of the voice coil motor drives the lens module to move so that the lens module finally moves to the target position, wherein a magnet is installed on the lens module, and the movement of the lens module will cause the z-axis magnetic field at the TMR magnetic sensor to change.

6. The magnetic position sensor according to claim 5, characterized in that The magnetic position sensor is fixed on the substrate, the magnet is fixed on the lens module, and the lens module is fixed on the moving part of the voice coil motor. The drive control circuit provides a drive current to the coil of the voice coil motor to drive the moving part of the voice coil motor to move the lens module to a target position.

7. An anti-shake camera, characterized in that: It includes: A voice coil motor comprising a moving part; a lens module mounted on the moving portion of the voice coil motor, wherein the moving portion of the voice coil motor is capable of driving the lens module to move; a magnet fixed to the lens module; A chip of the magnetic position sensor according to any one of claims 1 to 6 is fixedly mounted on the substrate, and the chip is spaced apart and opposite to the magnet.

8. The anti-shake camera according to claim 7, wherein: The magnet has an N pole and an S pole arranged along the x-axis, a center line of the magnet parallel to the z-axis is perpendicular to the surface of the chip and aligned with a center line of the magnetic position sensor parallel to the z-axis, The movement of the magnet along the x-axis causes a change in the magnetic field sensed by the magnetic position sensor.

9. The anti-shake camera according to claim 7, wherein: The magnet has an N pole and an S pole arranged along the z-axis, a center line of the magnet parallel to the z-axis is perpendicular to the surface of the chip and aligned with a center line of the magnetic position sensor parallel to the z-axis, The movement of the magnet along the z-axis causes a change in the magnetic field sensed by the magnetic position sensor.

Images