CN103454749B - A kind of closed loop lens drive motor - Google Patents

Abstract

The invention discloses a closed-loop lens driving motor, which comprises a base, and a lens carrier is arranged inside the base, and is characterized in that a PCB board is arranged outside the lens carrier, a coil is arranged inside the PCB board, a Hall element is arranged at the center of the coil, and a PCB board is arranged outside A yoke is provided, a magnet is provided on the side of the lens carrier close to the PCB, and a shielding cover is provided outside the base. The principle of the driving motor is that the energized coil generates a magnetic field, which generates a force with the magnetic field of the magnet to push the lens carrier forward and backward. The Hall element in the center of the coil senses the position of the magnet and outputs an electrical signal. After the control chip receives the electrical signal The calculation is performed, and the output signal controls the magnitude of the input current of the coil to change, thereby controlling the lens carrier to achieve balance at a certain position. The present invention adopts the Hall element to realize the feedback, and because the control chip has the memory capability, the adjusting response speed is fast.

Description

A closed-loop lens drive motor

technical field

The invention relates to a lens driving device, in particular to a closed-loop lens driving motor applied to a camera, a video camera or a mobile phone with a camera function to drive the lens to move and adjust the focal length.

Background technique

With the diversification of functions of digital products, digital devices equipped with video cameras or cameras, such as mobile phones, multimedia players, etc., have been developed rapidly and widely used. The above-mentioned video cameras or cameras usually adopt lenses with adjustable focal length or auto-focus, and the adjustment process is to change the position of the lens, and a drive motor is usually used to drive the lens to move.

The driving device for adjusting the focal length of a traditional camera usually includes stepping motors, gears, cams, and connecting rods. A lens structure with a stable autofocus function disclosed in Chinese patent document CN2938165Y includes a housing, a motor, a first A gear, a second gear, a lens module and an elastic component, the motor is arranged in the casing, the first gear is arranged in the casing and fixed on the axis of the motor, the second gear is arranged in the The upper surface of the second gear has a helical slope, and the lens module is arranged in the housing, and the lens module has a helical slope with the second gear. Bumps with sloped contact. It involves motor, two gears, housing, helical bevel, bump, lens module and many other components, which makes the size of the camera larger and the transmission load, so it is difficult to adapt to the trend of miniaturization.

In order to meet the requirements of camera miniaturization, more and more adopt a driving device that utilizes a magnetic field to generate power. In the solution disclosed in a lens driving device with the Chinese invention patent No. ZL200410017724.3, it includes a cylindrical yoke ring installed on the base, a magnet and a coil are arranged inside the yoke ring, and the inner circumference of the coil is A lens with a lens support is arranged on the side; the magnet and the coil are placed inside the yoke ring, the coil is fixed on the outer periphery of the lens support on the inner peripheral side of the yoke ring, and the lens support extends into the In the cylindrical yoke ring and can move in the yoke ring, the lens driving device also includes annular front side reeds and rear side reeds, and their outer peripheral ends are fixed to the front side of the yoke ring There is also a small cap, which fixes the inner peripheral end of the front reed on the front side of the lens support, and a frame, which fixes the outer peripheral end of the front reed on on the front side of the yoke ring.

The above-mentioned lens driving device uses the electromagnetic induction of the magnet to cause the lens support placed in the middle of the yoke ring to be displaced by the parallel electromagnetic force, and at the same time, the front reed and the rear reed placed on the lens support produce a reaction force , when the electromagnetic force acting on the lens support and the spring force of the reed reach a balance, the lens support remains in a certain position; that is, the electromagnetic force generated by the coil is opposed to the front reed and the force of the rear reed drives the lens support to move toward the optical axis.

Although the above-mentioned lens driving device can limit the movement of the lens support body through the reeds at the front and rear sides, it has the performance of anti-bump and impact and has good image quality. However, generally speaking, these lens driving devices are all open-loop devices, so there are disadvantages of slow response speed and large power consumption.

Contents of the invention

The object of the present invention is to provide a closed-loop lens driving motor with a faster response speed.

In order to achieve the above object, the technical solution of the present invention is: a closed-loop lens driving motor, including a base, and a lens carrier is arranged inside the base, which is characterized in that a PCB board is arranged outside the lens carrier, a coil is arranged inside the PCB board, and a coil is arranged at the center of the coil. There is a Hall element, a yoke is arranged on the outside of the PCB, a magnet is arranged on the outside of the lens carrier close to the PCB, and a shielding cover is arranged on the outside of the base.

According to a specific embodiment of the present invention, the gap between the coil and the magnet is not greater than 0.1mm. The magnet is composed of two symmetrical parts up and down. The upper and lower parts are the same in size and opposite in polarity. The magnetic field generated by the electrification of the coil is correspondingly opposite to the polarity of the magnet. The motor is also provided with a control unit, the input end of the control unit is connected to the Hall element, the output end of the control unit is connected to the coil, and the control unit includes a control chip and a control circuit connected to the control chip. Ceramic balls are arranged between the lens carrier and the base to reduce friction when the lens carrier moves.

The operating principle of the drive motor is that the energized coil generates a magnetic field, which generates a force with the magnetic field of the magnet to push the lens carrier forward and backward. The Hall element in the center of the coil senses the position of the magnet and outputs an electrical signal. After the control chip receives the electrical signal The calculation is performed, and the output signal controls the magnitude of the input current of the coil to change, thereby controlling the lens carrier to achieve balance at a certain position. The present invention adopts the Hall element to realize the feedback, and because the control chip has memory capability, the adjustment response speed is fast.

Description of drawings

Fig. 1 is a blast view of an embodiment of the present invention.

Figure 2 is a top view of this embodiment.

Figure 3 is a schematic diagram of this embodiment.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and examples.

As shown in Figure 1,

A lens drive motor comprising

shielding cover 1,

front cover 2,

Base 3,

Carrier 4,

magnet 5,

PCB board 6,

Ball 7,

Yoke iron 8,

Wherein the PCB board 6 is provided with a coil 9 and a Hall element 10 .

As shown in Figure 2 and Figure 3, the lens carrier 4 is located in the base 3, the lens carrier 4 is provided with a PCB board 6 outside, the inside of the PCB board 6 is provided with a coil 9, the center of the coil 9 is provided with a Hall element 10, and the outside of the PCB board 6 A yoke 8 is provided, a magnet 5 is provided on the outer side of the lens carrier 4 near the coil, a front cover 2 is provided at the front end of the base 3 , and a shielding cover 1 is provided outside the base and the front cover 2 .

The magnet is composed of two symmetrical parts up and down. The upper and lower parts are the same in size and opposite in polarity. The magnetic field generated by the electrification of the coil is correspondingly opposite to the polarity of the magnet. The motor is also provided with an external control unit, the input end of the external control unit is connected to the Hall element, the output end of the external control unit is connected to the coil, the input end and the output end of the external control unit are connected to the PCB Board electrical connection connections. The external control unit is provided with a chip and a control circuit connected with the chip. The PCB board is a U-shaped structure, one end of which is located on one side of the lens carrier 4, and a coil, a Hall element and a reinforcing iron plate are arranged, and the other end is located on the other side of the lens carrier, and an external pin is provided to communicate with the external Control unit connection. The chip of the external control unit is connected to the 4 Hall elements in the motor through the interface on the PCB board. The magnetic field intensity induced by the Hall elements is used to feed back the converted electrical signal to the chip, and then through the pre-set parameter, to achieve motor standstill or motion.

The energized coil generates a magnetic field, which creates a force with the magnetic field of the magnet to push the lens carrier forward and backward. The Hall element in the center of the coil senses the position of the magnet and outputs an electrical signal. The control chip performs calculations after receiving the electrical signal, and the output signal controls the The magnitude of the input current of the coil changes, thereby controlling the lens carrier to reach a balance at a certain position. The present invention adopts the Hall element to realize the feedback, and because the control chip has memory capability, the adjustment response speed is fast.

The energized coil generates a magnetic field force in the magnetic field. The magnet of a traditional motor is the stator, and the coil is the mover. However, in the solution of the present invention, the coil is fixed and the magnet is dynamic, so it is opposite to the traditional motor.

The shielding shell has the functions of grounding anti-static and electromagnetic shielding during the external connection of the motor. After the shielding cover is added, it can greatly reduce the signal interference of the high-frequency module of the mobile phone when the motor coil is working, and enhance the call quality. After the motor shield is grounded, it can prevent the static electricity generated by the signal and other frictions from causing damage to the motor.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to the above descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (1)

1. A closed-loop lens drive motor, comprising a base, a lens carrier is provided in the base, and it is characterized in that a PCB board is provided outside the lens carrier, a coil is provided on the inside of the PCB board, a Hall element is provided at the center of the coil, and a lens carrier is provided on the outside of the PCB board. Iron yoke, the outside of the lens carrier is provided with a magnet on the side of the PCB, and the base is provided with a shield cover. The gap between the coil and the magnet is not greater than 0.1mm. The magnet is composed of two symmetrical parts up and down. The same size and opposite polarity, the magnetic field generated by the coil energization is opposite to the polarity of the magnet, the motor is also provided with a control unit, the input end of the control unit is connected to the Hall element, and the output end of the control unit Connected to the coil, the control unit includes a control chip and a control circuit connected to the control chip, ceramic balls are arranged between the lens carrier and the base, the PCB board is a U-shaped structure, one end of which is located on one side of the lens carrier, and the coil is set , Hall element, the other end is located on the other side of the lens carrier, and is provided with external pins, which are connected to the external control unit. The chip of the external control unit is connected to the 4 internal pins of the motor through the external pins of the PCB board. The connection of Er components.