CN114040072A

CN114040072A - Camera mechanism, driving method thereof and electronic equipment

Info

Publication number: CN114040072A
Application number: CN202111316129.XA
Authority: CN
Inventors: 吴少颖
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2022-02-11

Abstract

The application relates to a camera mechanism, a driving method thereof and an electronic device. The driving method comprises the following steps: the driving motor is started at a first rotating speed and performs accelerated rotation; when the driving motor reaches the second rotating speed, the driving motor rotates at a constant speed at the second rotating speed; and the second rotating speed is greater than the first rotating speed and is used for enabling the camera module to pop up quickly. The camera mechanism comprises a driving motor, a transmission assembly and a camera module, wherein the driving motor can execute a driving method, and the transmission assembly comprises a screw rod and a screw nut which are in threaded connection; the camera module comprises a lens group, and the lens group is connected with the screw rod nut and can reciprocate along the screw rod; the driving motor is configured to drive the screw rod to rotate so as to enable the lens group to move back and forth along the screw rod. In this way, the output torque of the driving motor is always larger than the required torque, so that the camera module can be rapidly popped out, the time of the popping-out process is shortened, and the driving motor can be prevented from being out of step.

Description

Camera mechanism, driving method thereof and electronic equipment

Technical Field

The application relates to the technical field of electronic equipment, in particular to a camera mechanism, a driving method thereof and electronic equipment.

Background

The pop-up camera is one of the important methods for realizing the miniaturization of the camera module at present, but the pop-up power of the pop-up camera comes from a driving motor such as a stepping motor, and the speed is increased too fast due to the torque characteristic of the stepping motor, so that the stepping motor is easy to step out; the speed is accelerated too slowly, and the time of popping up the camera module is overlong, influences user experience.

Disclosure of Invention

The application provides a camera mechanism, a driving method thereof and an electronic device.

The application provides a driving method of a camera mechanism, wherein the camera mechanism comprises a driving motor and a camera module, and the driving method comprises the following steps:

the driving motor is started at a first rotating speed and performs accelerated rotation;

when the driving motor reaches a second rotating speed, the driving motor rotates at a constant speed at the second rotating speed;

and the second rotating speed is greater than the first rotating speed and is used for enabling the camera module to pop up quickly.

The embodiment of the present application further provides a camera mechanism, including:

a driving motor capable of performing the driving method;

the transmission assembly comprises a screw rod and a screw nut which are in threaded connection; and

the camera module comprises a lens group, and the lens group is connected with the screw rod nut and can reciprocate along the screw rod;

the driving motor is configured to drive the screw rod to rotate so as to enable the lens group to move back and forth along the screw rod.

The embodiment of the application also provides an electronic device, which comprises the camera mechanism.

The driving method of the camera shooting mechanism provided by the embodiment of the application makes the driving motor do accelerated motion in the starting stage, so that the output torque of the driving motor is always larger than the required torque, the camera module can be rapidly popped out, the time of the popping-out process is reduced, and the driving motor can be prevented from being out of step.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic perspective view of an electronic device provided in an embodiment of the present application;

FIG. 2 is a schematic cross-sectional view of the electronic device shown in FIG. 1 along direction A-A;

FIG. 3 is a schematic front view of a camera mechanism in the electronic device shown in FIG. 2;

FIG. 4 is a schematic cross-sectional view of a variation of the camera mechanism shown in FIG. 3;

FIG. 5 is a schematic front view of yet another variation of the camera mechanism shown in FIG. 3;

FIG. 6 is a schematic top view of the camera mechanism shown in FIG. 5;

FIG. 7 is a perspective view of the drive motor, first gear, and switching assembly of the camera mechanism of FIG. 6 in cooperation;

FIG. 8 is a perspective view of the switching assembly shown in FIG. 7;

FIG. 9 is an exploded schematic view of the switching assembly shown in FIG. 8;

fig. 10 is a schematic flowchart of a camera mechanism driving method provided in an embodiment of the present application;

FIG. 11 is a schematic view of the torque-frequency characteristics of the drive motor;

FIG. 12 is a schematic illustration of drive motor first speed output torque, second speed output torque and torque demand over time;

FIG. 13 is a schematic representation of the rotational speed of the drive motor over time in the present application;

FIG. 14 is a graphical illustration of output torque versus requested torque over time for the rotational speeds illustrated in FIG. 13;

FIG. 15 is a first graphical representation of the rotational speed of the drive motor as a function of step number;

FIG. 16 is a second graphical illustration of the rotational speed of the drive motor as a function of the number of steps;

FIG. 17 is a third graphical representation of the rotational speed of the drive motor as a function of step number.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be noted that the following examples are only illustrative of the present application, and do not limit the scope of the present application. Likewise, the following examples are only some examples and not all examples of the present application, and all other examples obtained by a person of ordinary skill in the art without any inventive work are within the scope of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Referring to fig. 1, fig. 1 is a schematic perspective view of an electronic device according to an embodiment of the present disclosure. The present application provides an electronic device 1000. Specifically, the electronic device 1000 may be any of various types of computer system devices (only one modality shown in fig. 1 by way of example) that are mobile or portable and that perform wireless communications. Specifically, the electronic device 1000 may be a mobile phone or smart phone (e.g., an iPhone (TM) based, Android (TM) based phone), a Portable gaming device (e.g., a Nintendo DS (TM), a PlayStation Portable (TM), a Game Advance (TM), an iPhone (TM)), a laptop, a PDA, a Portable Internet device, a music player and data storage device, other handheld devices and devices such as a headset, and the like, and the electronic device 1000 may also be other wearable devices that require charging (e.g., a Head Mounted Device (HMD) such as an electronic bracelet, an electronic necklace, an electronic device or a smart watch).

The electronic device 1000 may also be any of a number of electronic devices including, but not limited to, cellular telephones, smart phones, other wireless communication devices, personal digital assistants, audio players, other media players, music recorders, video recorders, other media recorders, radios, medical devices, vehicle transportation equipment, calculators, programmable remote controllers, pagers, laptop computers, desktop computers, printers, netbook computers, Personal Digital Assistants (PDAs), Portable Multimedia Players (PMPs), moving Picture experts group (MPEG-1 or MPEG-2) Audio layer 3(MP3) players, portable medical devices, and digital cameras and combinations thereof.

Referring to fig. 2, fig. 2 is a schematic cross-sectional view of the electronic device shown in fig. 1 along a direction a-a. In some cases, the electronic device 1000 may perform multiple functions (e.g., playing music, displaying videos, storing pictures, and receiving and sending telephone calls). If desired, the electronic device 1000 may be a device such as a cellular telephone, media player, other handheld device, wrist watch device, pendant device, earpiece device, or other compact portable device.

The embodiment of the application provides an electronic device 1000, and the electronic device 1000 may include a rear cover 300, a display screen 200 and a camera mechanism 100, wherein the rear cover 300 and the display screen 200 may enclose a fixing space for accommodating devices such as the camera mechanism 100, a motherboard, and a battery, and a partial structure of the camera mechanism 100 is arranged on the rear cover 300 in a penetrating manner.

Referring to fig. 3, fig. 3 is a schematic front view of a camera mechanism in the electronic device shown in fig. 2. In one embodiment, the camera mechanism 100 may include a camera module 10, a transmission assembly 20, and a driving motor 30. The camera module 10 may include a housing 11, a lens group 12, an image sensor 13, and a module substrate 14. The housing 11 may have a receiving cavity for receiving and fixing the lens assembly 12, the image sensor 13 is located between the lens assembly 12 and the module substrate 14, and the image sensor 13 is located on the module substrate 14 and is disposed opposite to the lens assembly 12 at a distance. The transmission assembly 20 includes a screw 21 and a screw nut 22, which are connected by screw threads, wherein the screw 21 is fixedly connected with a rotating shaft of the driving motor 30 and can be driven by the driving motor 30 to rotate, and the screw nut 22 is fixedly connected with the housing 11. The driving motor 30 may be a stepping motor, a piezoelectric motor, etc., and is not particularly limited herein.

It can be understood that the driving motor 30 can drive the lead screw 21 to rotate, so that the lead screw nut 22 and the housing 11 fixedly connected with the lead screw nut 22 reciprocate along the axial direction of the lead screw 21, and the distance between the lens group and the image sensor 13 is changed, so that the camera module 10 can be switched between the compression state and the working state back and forth, and the purpose of miniaturization and space saving of the camera module 10 is achieved.

Specifically, the housing 11 is a carrier part of the camera module 10, and is mainly used for driving the lens group 12 to move to a preset imaging position, and meanwhile, the housing 11 further integrates an optical anti-shake module and an automatic focusing module, so that the lens group 12 can accurately move in a hundred-micron order, and accurate focusing and clear imaging in an imaging process are further ensured. The lens group 12 is used to collect external light and sharply image a subject on an imaging surface. The image sensor 13 is used for receiving light passing through the lens group 12 and converting the collected light signals into electrical signals for forming a picture file. The module substrate 14 is used to fix and carry the image sensor 13, the transmission assembly 20, the switching assembly 50 and the driving motor 30.

The transmission assembly 20 may include a lead screw 21 and a lead screw nut 22, wherein the lead screw 21 and the lead screw nut 22 are in threaded connection with the lead screw 21 and can move linearly along the lead screw 21. The lead screw nut 22 is fixedly connected to the housing 11 and can drive the housing 11 and the lens set 12 fixed in the housing 11 to reciprocate along the lead screw 21. The driving motor 30 can be coaxially arranged with the screw rod 21 and directly drive the screw rod 21 to rotate. Optionally, a fixing hole (not shown) is formed in the module substrate 14, and one end of the lead screw 21 can be inserted into the fixing hole, so that the lead screw 21 is rotatably connected with the module substrate 14, thereby ensuring the reliability of the rotation of the lead screw 21.

Referring to fig. 4, fig. 4 is a schematic cross-sectional view of a variation of the camera mechanism shown in fig. 3. In another embodiment, the camera mechanism 100 may include not only the camera module 10, the transmission assembly 20 and the driving motor 30, but also the speed reduction assembly 40. The speed reducing assembly 40 may include a first gear 41 and a second gear 42 capable of meshing with each other, wherein the first gear 41 is fixedly connected to the rotating shaft of the driving motor 30 and is driven by the driving motor 30 to rotate, and the second gear 42 is fixedly connected to the lead screw 21 and is coaxially disposed. The diameter of the first gear 41 is smaller than that of the second gear 42, that is, the rotation speed of the first gear 41 is much greater than that of the second gear 42, so that the screw 21 can rotate at a proper rotation speed.

It should be noted that the terms "first", "second" and "third" in the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise.

In this embodiment, the first gear 41 may be a helical gear, the second gear 42 may be a helical gear, and the first gear 41 is engaged with the second gear 42, so that the rotating shaft of the motor may form an included angle with the lead screw 21, so that the driving motor 30 can adapt to the fixing space of the electronic device 1000, and further, the fixing space is fully utilized.

In other embodiments, the first gear 41 may be a straight gear, the second gear 42 may be a straight gear, and the first gear 41 is engaged with the second gear 42, so that the rotating shaft of the motor may be arranged in parallel and offset with the screw rod 21, and the camera mechanism 100 can save space and maintain a proper rotating speed, and is reasonable and orderly in layout.

Referring to fig. 5 to 7, fig. 5 is a schematic front view of still another variation of the camera mechanism shown in fig. 3, fig. 6 is a schematic top view of the camera mechanism shown in fig. 5, and fig. 7 is a perspective view of the camera mechanism shown in fig. 6 in which the driving motor, the first gear and the switching assembly are engaged. In yet another embodiment, the camera mechanism 100 may include not only the camera module 10, the transmission assembly 20, the speed reduction assembly 40 and the driving motor 30, but also the switching assembly 50. The switching assembly 50 is located between the first gear 41 and the second gear 42 of the speed reducing assembly 40, and can be engaged with the first gear 41 and the second gear 42 at the same time, so as to control the transmission of the first gear 41 and the second gear 42, and further control the transmission of the driving motor 30 and the transmission assembly 20.

Referring to fig. 8 and 9 together, fig. 8 is a perspective view of the switching assembly shown in fig. 7, and fig. 9 is an exploded view of the switching assembly shown in fig. 8. Specifically, the switching assembly 50 may include a fixed shaft 51, a transfer gear 52 and a driving member 53, wherein the transfer gear 52 is sleeved on the fixed shaft 51 and can be engaged with the second gear 42, so that the switching assembly 50 can drive the second gear 42 to rotate. The driving member 53 can be connected to the fixed shaft 51 and can drive the transfer gear 52 to move closer to or away from the second gear 42. It is understood that the intermediate gear 52, when adjacent to the second gear 42, can engage with the second gear 42 to move the transmission assembly 20; when the transfer gear 52 is away from the second gear 42, the second gear 42 is in an unpowered state, i.e., the switching assembly 50 is not capable of powering the transmission assembly 20.

It is understood that the transfer gear 52 can be engaged with the first gear 41 and the second gear 42 simultaneously, so that the driving motor 30 can drive the transmission assembly 20; the transfer gear 52 can also be simultaneously away from the first gear 41 and the second gear 42, so that the driving motor 30 and the transmission assembly 20 can be independent of each other.

Alternatively, the fixed shaft 51 may include a shaft 511 and a supporting plate 512 fixed to one end of the shaft 511, and the transfer gear 52 abuts against the supporting plate 512 and can rotate around the shaft 511, that is, the transfer gear 52 is disposed at a gap from the shaft 511, so that the transfer gear 52 and the shaft 511 do not move synchronously. The driving member 53 is fixed at an end of the shaft 511 away from the supporting plate 512, and is used for driving the fixed shaft 51 and the transfer gear 52 sleeved on the fixed shaft 51 to move away from the second gear 42 along the axial direction of the shaft 511.

Specifically, the driving member 53 may include a magnetic portion 521 and a coil portion 522, the magnetic portion 521 is fixedly connected to an end of the shaft 511 away from the supporting plate 512, and the coil portion 522 is sleeved on the magnetic portion 521. When the coil portion 522 is energized, a magnetic field is generated, the magnetic portion 521 can generate a force in the magnetic field along the axial direction of the shaft 511, and the magnetic portion 521 and the shaft 511 connected to the magnetic portion 521 are driven to move away from the second gear 42 along the direction of the shaft 511, that is, the coil portion 522 drives the magnetic portion 521 and the shaft 511 to move away from the second gear 42 along the axial direction of the shaft 511 under the condition of energization.

Further, the switching assembly 50 may further include a sleeve 54 sleeved on an end of the shaft 511 away from the supporting plate 512, that is, the magnetic portion 521 is sleeved in the sleeve 54. The coil portion 522 is fixed inside the sleeve 54, so that the magnetic portion 521 can drive the shaft 511 to move relative to the sleeve 54. The inner wall of the sleeve 54 may be provided with an annular groove 541, the coil portion 522 is received and fixed in the annular groove 541, and the inner surface of the coil portion 522 is flush with the inner wall of the sleeve 54 or slightly recessed in the inner wall of the sleeve 54 to ensure that the shaft 511 can move in the sleeve 54.

Furthermore, the switching assembly 50 may further include an elastic member 55 (e.g., a spring), one end of the elastic member 55 abuts against the surface of the magnetic portion 521 facing away from the shaft 511, and the other end abuts against the bottom wall of the sleeve 54, wherein the elastic member 55 is always in a compressed state. When the coil is energized, the magnetic portion 521 can generate a magnetic lifting force along the axial direction of the shaft 511 and toward the bottom wall of the sleeve 54, and the elastic member 55 is further compressed while the magnetic portion 521 is close to the bottom wall of the sleeve 54, so as to limit the moving distance of the shaft 511 and the transfer gear 52 sleeved on the shaft 511, and at this time, the transfer gear 52 is in the first state. When the power is turned off, the magnetic lifting force (i.e., the interaction force) between the magnetic portion 521 and the coil portion 522 disappears, and the elastic member 55 can press the magnetic portion 521, so that the shaft 511 and the transfer gear 52 sleeved on the shaft 511 are away from the bottom wall of the sleeve 54 until the transfer gear 52 is meshed with the second gear 42, and at this time, the transfer gear 52 is in the second state. It can be understood that the transfer gear 52 is always in the second state to ensure that the camera module 10 can be in the working state all the time; when the electronic device 1000 needs the vibration motor assembly to vibrate alone, such as the vibration of a mobile phone alarm, the vibration of an incoming call, etc., the transfer gear 52 can be in the first state.

In another embodiment, the driving member 53 is fixedly connected to the fixed shaft 51, and the driving member 53 can drive the fixed shaft 51 and the transfer gear 52 sleeved on the fixed shaft 51 to move away from the second gear 42 along a predetermined direction, wherein the predetermined direction is perpendicular to the axial direction of the shaft 511.

Specifically, the fixed shaft 51 may include a shaft 511 and a supporting plate 512 fixed to an end of the shaft 511, and the transfer gear 52 abuts against the supporting plate 512 and is capable of rotating around the shaft 511, that is, the transfer gear 52 is disposed at a gap from the shaft 511, so that the transfer gear 52 and the shaft 511 do not move synchronously. The driving member 53 is fixed at an end of the shaft 511 away from the supporting plate 512, and is used for driving the fixed shaft 51 and the transfer gear 52 sleeved on the fixed shaft 51 to move away from the second gear 42 along the axial direction of the shaft 511.

Alternatively, the driving member 53 may be fixed to the fixed shaft 51 and can drive the transfer gear 52 to move in a plane perpendicular to the axis of the fixed shaft 51. The driving member 53 may be a telescopic cylinder, a connecting rod, etc., and is not particularly limited thereto. When the driving member 53 is in a retracted state, such as a telescopic cylinder, the transfer gear 52 is far away from the second gear 42, and the transfer gear 52 is in a first state; when the driving member 53 is in the extended state, such as the telescopic cylinder, the relay gear 52 is engaged with the second gear 42, and the relay gear 52 is in the second state. It can be understood that the transfer gear 52 is always in the second state to ensure that the camera module 10 can be in the working state all the time; when the electronic device 1000 needs the vibration motor assembly to vibrate alone, such as the vibration of a mobile phone alarm, the vibration of an incoming call, etc., the transfer gear 52 can be in the first state.

With reference to fig. 4, optionally, the camera mechanism 100 may further include a position sensor 60, where the position sensor 60 is disposed on the lead screw 21 and is used to detect a relative displacement of the lead screw nut 22 on the lead screw 21, so as to determine a distance between the lens assembly and the module substrate 14, and further enable the lens assembly 12 to be focused accurately and quickly in an imaging process.

The switching assembly 50 provided by the embodiment of the application is configured to be engaged with the second gear 42 through the transfer gear 52, so as to enable the lens group 12 to reciprocate along the lead screw 21, and the transfer gear 52 is further configured to be away from the second gear 42, so as to enable the power component to vibrate independently, so that the vibration motor assembly can drive the camera module 10 to pop up, and can respond to the reminding function of the electronic device 1000, thereby improving the utilization rate of components in the electronic device 1000 and saving the internal space of the electronic device 1000.

Referring to fig. 10, fig. 10 is a schematic flow chart of a camera mechanism driving method according to an embodiment of the present application. The embodiment of the present application further provides a method for driving the camera mechanism 100, which includes the following steps:

step S01, the driving motor 30 is started at the first rotation speed and performs an acceleration rotation;

step S02, when the driving motor 30 reaches the second rotation speed, the driving motor 30 rotates at the second rotation speed;

the second rotation speed is greater than the first rotation speed, and is used for enabling the output torque of the driving motor 30 to be greater than the required torque of the transmission assembly 20, so that the camera mechanism is rapidly ejected.

Wherein, the driving motor 30 is started at a first rotation speed and performs accelerated rotation as a starting stage, and the driving motor 30 performs uniform rotation at a second rotation speed as a stabilizing stage.

Referring to fig. 11 and 12 together, fig. 11 is a schematic diagram of the torque-frequency (output torque — rotation speed) characteristic of the driving motor, and fig. 12 is a schematic diagram of the time-dependent changes of the first rotation speed output torque, the second rotation speed output torque and the required torque of the driving motor. The pull-in torque in fig. 11 is an acceleration torque that can ensure starting, stopping and reversing of the motor without step-out, that is, the pull-in torque is equal to the required torque of the transmission assembly 20; the pull-out torque is the maximum torque which can be output by the shaft end when the motor is operated at a continuous constant speed on the premise of no step-out, namely the output torque of the driving motor.

It can be understood that when the driving motor 30 is driven at a high rotation speed (i.e. the second rotation speed, for example, 1000pps), the driving motor 30 is out of step during the starting phase, i.e. the output torque of the driving motor 30 is smaller than the required torque (load, resistance generated by friction), and the motor receives the signal but does not synchronously move by the corresponding step angle. When driving at a low rotational speed (i.e., the first rotational speed, for example, 500pps), although it is possible to ensure that the output torque of the drive motor 30 is greater than the required torque, since the rotational speed of the drive motor 30 is low, it takes a longer time for the lead screw nut 22 to move the same distance on the lead screw 21.

Referring to fig. 13 and 14, fig. 13 is a schematic diagram of a change of a rotation speed of a driving motor with time in the present application, and fig. 14 is a schematic diagram of a change of an output torque corresponding to the rotation speed shown in fig. 13 and a required torque with time.

In the present application, when the required torque is large in the starting stage (i.e. the initial stage), the low-speed driving is adopted and the acceleration stage is immediately entered, and the rotation speed of the driving motor 30 can be gradually increased in the acceleration stage along with the reduction of the required torque, wherein the output torque is always greater than the required torque, so as to avoid the step-out problem of the driving motor 30 until the driving motor 30 reaches the second rotation speed. And further, the driving motor 30 is driven at the second rotation speed as much as possible, so as to reduce the ejection time of the camera module 10 as much as possible.

Referring to fig. 15, fig. 15 is a schematic diagram of a first functional relationship between the rotation speed and the number of steps of the driving motor. Let the first rotation speed be a, the second rotation speed be a + B, the start-up phase of the driving motor 30 completes the acceleration process in the preset total step number N, and in order to realize the smooth change of the driving motor 30 from the first rotation speed to the second rotation speed, a rotation speed slope function may be introduced:

the process of changing the rotation speed of the driving motor 30 will be described, where x is the number of steps of the driving motor 30, and m (x) is the value of the slope of the rotation speed of the driving motor 30 corresponding to the number of steps. The speed function is characterized in that, within a defined range, the speed function has a limited value range (for example, the value range of the speed function is (0, 1)), so that the acceleration process of the drive motor 30 is always switched between two specific speeds (for example, a and a + B).

Referring to fig. 16, fig. 16 is a diagram illustrating a second functional relationship between the rotation speed and the number of steps of the driving motor. Let a be the first rotation speed of the driving motor 30, a + B be the second rotation speed of the driving motor 30, and B be the difference between the second rotation speed of the driving motor 30 and the first rotation speed, the value range of the rotation speed function f (x) falls within the range of [ a, a + B ].

The rotation speed function of the driving motor for smoothly accelerating from the first rotation speed to the second rotation speed is as follows:

f(x)＝A+B·m(x)；

that is to say

Where f (x) is the rotation speed function (equal to the input pulse frequency) of the driving motor 30 corresponding to the number of steps, it can be understood that A, B is the scaling factor of the value range of the function f (x) so that the value range of the rotation speed function f (x) falls within a reasonable range.

Referring to fig. 17, fig. 17 is a schematic diagram illustrating a third functional relationship between the rotation speed of the driving motor and the number of steps. However, in the acceleration process of the speed function f (x), part of the steps fall in the interval with negative steps, and the steps can only take natural numbers larger than zero, so that the slope factors a and b need to be increased for adjustment, that is, the smooth change of the driving motor 30 from the first rotating speed to the second rotating speed, and the speed slope function can be obtained

The slope factor a is used for adjusting the slope change ratio of the rotating speed, and the slope factor b is used for adjusting m (x) to 0 when x is 0. Further, let f (0) be a.

The form of the rotational speed function with the control coefficients further becomes:

the slope factors a and b can be determined by the following two equations:

wherein the content of the first and second substances,

the rotation function f (x) is the rotation function at x equal to 0, δ is an infinitesimal quantity for adjusting the intercept of the rotation function on the y axis (i.e. the rotation function f (0) is a + δ, i.e. the rotation function f (0) is not exactly equal to the first rotation a but is slightly larger than a by a small quantity, which is eliminated after the subsequent discretization process). And a x + b is 0, which is a midpoint equation, and the meaning of the equation is that when the equation is established, the value of the rotating speed function is

I.e. an intermediate position during acceleration. To meet the acceleration requirement for completion in N steps, we can determine that the midpoint equation holds at N/2 steps. Let δ be 1, the equation converts to:

the rotational speed function at this time is:

in a specific embodiment, the first rotation speed a of the driving motor 30 is 500pps, the difference between the second rotation speed and the first rotation speed B is 500pps, that is, the second rotation speed is 1000pps, and the preset total step number N of the start-up phase is 200 steps, then the rotation speed function of the driving motor 30 in the start-up phase may be:

in the actual working process, the rotating speed function can be discretized for convenient control, the whole starting stage is divided into a plurality of stages, and the rotating speed of a certain step number in each stage can be obtained by the rotating speed function. Specifically, please refer to table 1: and (4) a discretized rotating speed-step number relation table.

Table 1: discretized rotating speed-step number relation table

Step number (step)	Rotational speed (pps)
		0	500
40	512
		80	612
120	888
		160	988
200	1000

In the pop-up camera module, it is necessary to reduce the switching time between the retracted state and the operating state as much as possible, and therefore the overall operating time of the drive motor smoothly accelerating from the first rotational speed to the second rotational speed is an optimization target as a rotational speed function. In this premise, the slope of the rotation speed function always tends to increase, but due to the torque-frequency characteristic of the stepping motor, the higher the speed, the lower the torque, and therefore, there is a risk of the rotation speed being too high, resulting in step loss or stall.

Referring to table 2, table 2 gives the time and torque outputs corresponding to the number of steps in each stage based on table 1.

Table 2: time and torque output based on step number in each stage in Table 1

Staging (stage)	Step number (step)	Rotational speed (pps)	Time (ms)	Torque (mN. m)
					1	0	500	t1＝2	r1＝0.2
2	40	512	t2＝1.95	r2＝0.18
					3	80	612	t3＝1.63	r3＝0.17
4	120	888	t4＝1.13	r4＝0.15
					5	160	988	t5＝1.01	r5＝0.14
6	200	1000	t6＝1	r6＝0.13

As shown in table 2, the preset total number of steps N in the start phase is divided into N stages based on the discrete data of the number of steps in table 1, and the number of steps in each stage may be the same, for example, each stage in table 2 in this embodiment may include 40 steps; the number of steps of each sub-stage may also be different, for example, the first sub-stage may include 40 steps, and the second sub-stage may include 30 steps, which is not limited herein.

In this embodiment, the preset total number of steps N of the start-up phase is 200, the number of steps N is 6,

the total time cost can therefore be expressed as:

since each step takes time t_iDetermined by the speed function:

t_i＝1/f_i(x_ι) (the numerator unit is s, and the denominator is the number of steps);

the total time can thus be expressed as:

step_iis the number of steps in the ith phase.

That is, the total time for the accelerated motion of the driving motor 30 is:

wherein, the preset total step number of the acceleration stage of the driving motor 30 includes n stages; step_iIs the number of steps in the ith phase.

For given parameters a and b, corresponding T values may be calculated; the influence of the change of the T value on the T value can be obtained by calculating the partial derivative of the T value relative to a and b, and the updating direction (increasing or decreasing) of the a and b values is further obtained on the premise of reducing the acceleration time. Based on the method, a plurality of rotating speed function coefficients with different parameters can be generated, and the optimal coefficient combination is screened out according to whether the problems of step loss, clamping stagnation and the like exist in the actual working process due to insufficient torque.

The driving method of the camera shooting mechanism provided by the embodiment of the application makes the driving motor 30 do the accelerated motion in the starting stage, so that the output torque of the driving motor 30 is always larger than the required torque of the camera module 10, the camera module 10 can be rapidly popped up, the time of the popping-up process is reduced, and the driving motor 30 can be prevented from being out of step.

The above description is only a part of the embodiments of the present application, and not intended to limit the scope of the present application, and all equivalent devices or equivalent processes performed by the content of the present application and the attached drawings, or directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

1. A driving method of a camera mechanism is characterized in that the camera mechanism comprises a driving motor and a camera module, and the driving method comprises the following steps:

2. The drive method of claim 1, wherein the smooth acceleration of the drive motor from the first rotational speed to the second rotational speed is a function of rotational speed:

f(x)＝A+B·m(x)；

wherein m (x) is a rotational speed slope function for smooth acceleration of the drive motor from the first rotational speed to the second rotational speed:

a is the first rotating speed, A + B is the second rotating speed, B is the difference between the second rotating speed and the first rotating speed, e is a constant, and x is the running step number of the driving motor.

3. The drive method of claim 2, wherein the speed slope function for smooth acceleration of the drive motor from the first speed to the second speed is:

wherein, a and b are slope factors for controlling the speed of change of the rotating speed function value.

4. The driving method according to claim 3, wherein a and b satisfy the following equation:

where δ is an infinitesimal quantity used to adjust the intercept of the rotation speed function on the y-axis.

5. The driving method as claimed in any one of claims 2 to 4, wherein the driving motor is started at the first rotation speed and the preset total number of steps for making the accelerated rotation includes n number of stages, steps_iIs the number of steps in the ith phase; the total time for the accelerated motion of the drive motor is:

6. the driving method according to claim 5, wherein the driving motor, as a function of time consumed for each step:

t_i＝1/f_i(x_ι)；

the total time for the accelerated motion of the drive motor is:

7. a camera mechanism, comprising:

a drive motor capable of performing the driving method according to any one of claims 1 to 6;

8. The camera mechanism according to claim 7, further comprising a speed reduction assembly, wherein the speed reduction assembly comprises a first gear and a second gear which can be in meshing transmission, the first gear is fixedly connected with a rotating shaft of the driving motor, and the second gear is fixedly connected with the screw rod and coaxially arranged; wherein the rotational speed of the first gear is greater than the rotational speed of the second gear.

9. The camera mechanism of claim 8, wherein said first gear is a helical gear and said second gear is a helical gear for changing a direction of power output from a shaft of said drive motor.

10. The camera mechanism according to any one of claims 8 or 9, further comprising a switching assembly located between the first gear and the second gear for controlling the transmission of the drive motor and the transmission assembly; the switching component is configured to drive the screw rod to rotate, and is used for enabling the lens group to move back and forth along the screw rod; the switching assembly is further configured to be remote from the transmission assembly for individually vibrating the drive motor.

11. The camera mechanism of claim 7, wherein the camera module further comprises a housing, an image sensor and a module substrate, wherein the lens assembly is received and fixed in the housing, and the image sensor is located between the lens assembly and the module substrate and is fixedly connected to the module substrate; the shell is fixedly connected with the screw rod nut, so that the shell and the lens group can move back and forth along the screw rod to be close to or far away from the image sensor.

12. An electronic device, characterized in that it comprises a camera mechanism according to any one of claims 7-11.