Motor driving method, system, device and micro projection device

Abstract

Embodiments of the present application disclose a motor driving method, system, device and micro projection device. The motor driving method comprises: acquiring the number of beats of a motor and the pulse width of each beat, wherein the pulse width of each beat is the same; adjusting the pulse width of at least one beat to a target pulse width, and making the target pulse width greater than the pulse width; running the target pulse width of the beat to generate a driving pulse signal; and controlling the motor to run with the driving pulse signal. The scheme provided by the embodiments of the present application can keep the motor at a high working frequency and ensure the stability of the motor by changing the pulse width of the fixed number of beats of the motor.

Description

Technical Field

[0001] This application relates to the technical field of stepper motor control methods, and more specifically, to a motor driving method, system, device, and micro-projection equipment. Background Technology

[0002] In micro-projection devices, stepper motors are typically used to move the projection lens to achieve autofocus. Once the stepper motor structure is designed, its resonant frequency range can be determined. In micro-projection devices, to improve autofocus speed and maintain focusing precision, the stepper motor needs to operate at a higher drive frequency. This drive frequency is close to the stepper motor's resonant frequency range, which can easily lead to problems such as motor jamming or abnormal reverse rotation.

[0003] In existing technologies, the common approach is to reduce the driving frequency of the stepper motor to avoid its resonant frequency range, thereby increasing the output torque of the stepper motor. However, this reduces the angular velocity of the stepper motor, increasing the focusing time and severely impacting the overall user experience. Summary of the Invention

[0004] The purpose of this application is to provide a new technical solution for a motor driving method, system, device, and micro-projection equipment.

[0005] In a first aspect, embodiments of this application provide a motor driving method applied to a motor of a micro-projection device, the motor driving method comprising:

[0006] Obtain the number of steps of the motor and the pulse width of each step, wherein the pulse width of each step is the same;

[0007] The pulse width of at least one of the said number of beats is adjusted to a target pulse width, and the target pulse width is made greater than the pulse width, and the target pulse width of the number of beats is run to generate a drive pulse signal;

[0008] The motor is controlled to operate with the drive pulse signal.

[0009] Optionally, adjusting the pulse width of at least one of the number of beats to the target pulse width includes:

[0010] The pulse width of at least one of the starting beat count and the last beat count is adjusted to the target pulse width.

[0011] Optionally, adjusting the pulse width of at least one of the number of beats to the target pulse width includes:

[0012] The pulse width of the starting beat count and the pulse width of at least one between the starting beat count and the last beat count are adjusted to the target pulse width.

[0013] Optionally, adjusting the pulse width of at least one of the number of beats to the target pulse width includes:

[0014] The pulse width of the last beat number and the pulse width of at least one between the starting beat number and the last beat number are adjusted to the target pulse width.

[0015] Optionally, the target pulse width is at least twice the pulse width.

[0016] Optionally, the motor is a four-phase eight-step stepper motor, and the pulse widths of the first and eighth steps are adjusted to the target pulse width, making the target pulse width twice the pulse width, while keeping the pulse widths of the second to seventh steps unchanged, in order to generate the drive pulse signal.

[0017] Secondly, embodiments of this application provide a motor drive device, the motor drive device comprising:

[0018] The acquisition module acquires the number of steps of the motor and the pulse width of each step, wherein the pulse width of each step is the same;

[0019] The adjustment module adjusts the pulse width of at least one of the number of beats to a target pulse width, and makes the target pulse width greater than the pulse width, and runs the target pulse width of the number of beats to generate a drive pulse signal;

[0020] The control module controls the motor to run with the drive pulse signal.

[0021] Thirdly, embodiments of this application provide a controller, the controller comprising:

[0022] Memory, used to store computer programs; and

[0023] A processor for implementing the steps of the motor drive method as described above when executing the computer program.

[0024] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the motor driving method described above.

[0025] Fifthly, this application provides a micro-projection device, which includes: a projection lens, a focusing element, a motor, and a motor drive device, wherein the motor drive device is a motor drive device as described above; the motor drive device is connected to the motor, and the motor is connected to the projection lens through the focusing element.

[0026] The beneficial effects of this application are as follows:

[0027] This application provides a new driving scheme for motors. By changing the pulse width of the fixed number of steps of the drive motor, a certain regular drive pulse signal can be formed to drive the motor to run. This can maintain a high motor operating frequency and ensure the stability of the motor operation. The scheme of this application does not involve any improvement to the motor structure, and is low in cost and fast in time.

[0028] When the solution of this application embodiment is applied to a micro-projection device for automatic focusing, the focusing speed can be improved and the focusing precision can be maintained while ensuring the long-term stable operation of the motor.

[0029] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0031] Figure 1 This is a flowchart of a motor driving method provided in an embodiment of this application;

[0032] Figure 2 This is a comparison diagram of the driving timing of a traditional stepper motor and the motor drive provided in the embodiments of this application;

[0033] Figure 3 This is a schematic block diagram of a motor drive device provided in one embodiment of this application;

[0034] Figure 4 This is a structural block diagram of a controller provided in one embodiment of this application;

[0035] Figure 5 This is a structural block diagram of a micro-projection device provided in an embodiment of this application. Detailed Implementation

[0036] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0037] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0038] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0039] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0041] The following is in conjunction with the appendix Figures 1 to 5 The motor driving method, motor driving system, motor driving device, computer-readable storage medium, and micro-projection device provided in the embodiments of this application will be described in detail.

[0042] <Method Implementation>

[0043] Figure 1 This is a schematic flowchart of a motor driving method according to an embodiment of this application. This embodiment can be implemented by a controller, which may include a processor and can be connected to a driver IC circuit. The processor can issue drive pulse signals, which drive the motor to work via the driver IC circuit.

[0044] like Figure 1 As shown, the motor driving method provided in this application embodiment can be applied to drive the motor in a micro-projection device. This motor can be used to drive the projection lens in the micro-projection device to move, thereby achieving an automatic focusing function. The motor driving method may include steps S110 to S130.

[0045] Step S110: Obtain the number of beats of the motor and the pulse width of each beat, wherein the pulse width of each beat is the same.

[0046] In one example, the motor in step S110 can be a stepper motor, such as a four-phase stepper motor.

[0047] Furthermore, the motor in step S110 can be a four-phase eight-step stepper motor.

[0048] like Figure 2 As shown, Figure 2The diagram shows that a four-phase eight-step stepper motor can include eight steps in one cycle, numbered 1 to 8 in sequence. Each step corresponds to a set pulse width.

[0049] from Figure 2 The comparative examples shown demonstrate that the pulse width is the same for each number of pulses from 1 to 8. For example, the pulse width for each of the 1 to 8 pulses is set to T. The specific value can be flexibly designed as needed, and this is not limited in the embodiments of this application.

[0050] It should be noted that the motor driving method provided in this application embodiment is not limited to the four-phase eight-step stepper motor in the above example, but can also be other types of stepper motors, and this application embodiment does not impose specific limitations on them. The driven motor can be applied in a micro-projection device to drive the movement of the projection lens.

[0051] After step S110 is completed, the following step S120 can be performed:

[0052] Step S120, as follows Figure 1 and Figure 2 As shown, the pulse width of at least one of the number of beats is adjusted to a target pulse width, and the target pulse width is made greater than the pulse width, and the target pulse width of the number of beats is run to generate a drive pulse signal.

[0053] Existing stepper motor drive pulse signals have a fixed frequency and a fixed pulse width, such as Figure 2 As shown in the comparative example, the pulse width is the same for each step. When the stepper motor operates in the resonant frequency range, motor resonance is likely to occur, leading to abnormal situations such as motor jamming and reverse rotation.

[0054] It's important to note that the typical operation of a stepper motor involves the rotor rotating at a certain frequency under the influence of drive pulse signals. At this frequency, the rotor is prone to jitter during single-step operation, leading to resonance. This can cause unstable rotor positioning, preventing the rotor from stopping at the intended position, and resulting in the drive signal failing to drive the motor or poor reverse operation. Currently, a common method to avoid abnormal stepper motor resonance frequencies is to change the stepper motor's drive pulse frequency, keeping the pulse width consistent. However, this method significantly impacts the stepper motor's speed and output torque, potentially affecting focusing time and accuracy, thus impacting the user experience of the micro-projection device.

[0055] The motor driving method of this application, by changing the pulse width of at least one of the pulse counts, can form different pulse widths in a certain regular pattern, such as... Figure 2The motor timing diagram of this embodiment shown in the figure has the same pulse width of T for steps 2 to 7, while the pulse width of steps 1 and 8 is adjusted from T to 2T, forming different pulse widths in a certain regularity.

[0056] In the embodiments of this application, by using different pulse widths according to a certain pattern to drive the motor, the stability of the motor operation in or near the resonant frequency range can be guaranteed, avoiding motor resonance and thus preventing abnormal phenomena such as motor jamming or reversal.

[0057] The solution provided in this application embodiment does not reduce the motor's operating frequency, which differs from existing technologies. When the motor driving method of this application embodiment is applied to drive the motor in a micro-projection device, it can avoid adverse phenomena such as motor resonance without affecting the overall focusing time.

[0058] In the embodiments of this application, the motor is driven by using different pulse widths according to a certain pattern. The design is to appropriately widen the pulse width of some pulse counts, while keeping the pulse width of others fixed, in order to ensure minimal changes in the reduction of motor speed and prevent the motor from experiencing adverse effects on the overall focusing time due to excessively low speed.

[0059] In the embodiments of this application, by using different pulse widths according to a certain pattern to drive the motor, the output torque F of the motor can be increased, ensuring the stability of the projection lens focusing system and avoiding the phenomenon of single-step focusing jamming during the focusing process.

[0060] After step S120 is completed, we can proceed to step S130:

[0061] Step S130: Control the motor to run with the drive pulse signal.

[0062] After adjusting the pulse width of each step of the motor, the drive pulse signal can be updated to control the motor operation, thus ensuring the stability of the motor operation.

[0063] The solution provided in this application does not involve improvements to the motor structure; the stability of the motor operation can be guaranteed simply by changing the motor's driver program. This approach is low-cost and quick. It avoids the problems of long modification times and high costs associated with changing the motor structure in existing technologies.

[0064] When the motor driving method of this application embodiment is applied to a micro-projection device for automatic focusing, it can improve the focusing speed and maintain the focusing precision while ensuring the long-term stable operation of the motor.

[0065] In some examples of this application, adjusting the pulse width of at least one of the number of beats to the target pulse width may include: adjusting the pulse width of at least one of the starting beats and the last beats to the target pulse width.

[0066] like Figure 2 As shown, the pulse width of the starting and / or ending pulses of the motor within one cycle can be appropriately widened to obtain the target pulse width.

[0067] In the embodiments of this application, it is more preferred that the pulse width of the starting beat and the pulse width of the last beat are both adjusted to the target pulse width. That is, the pulse width of the starting beat and the last beat are widened, which makes it easier for the motor to start and stop at the start and stop times, thus making the motor operation more stable.

[0068] Of course, those skilled in the art may also widen the pulse width of either the starting beat count or the last beat count, depending on the specific circumstances. This application does not impose any restrictions on this.

[0069] For example, such as Figure 2 As shown, the motor to be driven is a four-phase eight-step stepper motor. The motor includes eight steps in one cycle, which can be in the order of step 1 to step 8. Before adjustment, the pulse width of each step is T. The pulse width of step 1 and step 8 is adjusted to, for example, 2T, to ensure the stable operation of the motor.

[0070] In some examples of this application, adjusting the pulse width of at least one of the number of beats to the target pulse width may include: adjusting the pulse width of the starting number of beats, and the pulse width of at least one between the starting number of beats and the last number of beats, to the target pulse width.

[0071] For example, taking a four-phase eight-step stepper motor as an example, such as Figure 2 As shown in the comparative example, the pulse widths of the 1st and 2nd pulses can be widened to achieve the target pulse width. This allows for a wider pulse at motor startup, resulting in a more stable motor start-up.

[0072] Of course, the starting beat count in the above example can also be replaced with the last beat count.

[0073] In some examples of this application, adjusting the pulse width of at least one of the beats to the target pulse width may include: adjusting the pulse width of the last beat and the pulse width of at least one between the starting beat and the last beat to the target pulse width.

[0074] For example, continuing with the example of a four-phase eight-step stepper motor, please continue as follows: Figure 2 As shown in the comparative example, you can also choose to widen the pulse width of the 7-beat and 8-beat pulses, i.e., adjust it to the target pulse width. This allows you to widen the pulse at the moment the motor stops, making the motor stop more stable, which also helps improve the stability of the motor's operation.

[0075] In some examples of this application, the target pulse width is at least twice the pulse width.

[0076] Preferably, the target pulse width is twice the pulse width.

[0077] In other words, when the pulse width is T, the target pulse width is 2T.

[0078] The motor driving method provided in this application can be applied to micro-projection devices to drive the motor therein, thereby achieving the focusing function of the projection lens. Therefore, the focusing time needs to be considered. If the pulse width is widened too much, the motor's operating speed may decrease excessively, which will affect the focusing time. Increased focusing time will negatively impact the user experience of the micro-projection device.

[0079] The following example, using a four-phase eight-step stepper motor, further illustrates why the effect is better when the target pulse width is twice the pulse width.

[0080] The traditional four-phase eight-step stepper motor has a driving speed of: n old =60 / 8T; where the pulse width from 1st to 8th pulse is T.

[0081] After driving the four-phase eight-step stepper motor using the motor driving method provided in this application, the pulse widths of steps 1 and 8 are adjusted to 2T, and the pulse widths of steps 2 to 7 are T. The driving speed of the four-phase eight-step stepper motor then becomes: n new =60 / 10T.

[0082] Based on the above n old and n new Comparison: Before and after pulse width adjustment, the motor drive pulse width did not decrease significantly, and the motor output torque did not decrease. At the same time, the motor speed was maintained to the maximum extent, thus not reducing the overall focusing time of the machine.

[0083] In one specific embodiment of this application, such as Figure 2 As shown, the motor is a four-phase eight-step stepper motor. The pulse widths of the first and eighth steps are adjusted to the target pulse width, making the target pulse width twice the pulse width, while keeping the pulse widths of the second to seventh steps unchanged, in order to generate the drive pulse signal.

[0084] The motor driving method provided in this application can improve the working stability of the motor simply by improving the motor driver program, without changing the motor's structural design. At the same time, it ensures that the motor's output torque does not decrease and its speed does not decrease significantly, thus avoiding changes to the focusing structure (such as torque and focusing stroke) of the projection lens in the micro-projection device.

[0085] <Device Embodiment>

[0086] Figure 3 This is a schematic block diagram of a motor drive device according to one embodiment.

[0087] like Figure 3 As shown, the motor drive device 300 may include:

[0088] The acquisition module 310 acquires the number of steps of the motor and the pulse width of each step, wherein the pulse width of each step is the same;

[0089] The adjustment module 320 adjusts the pulse width of at least one of the number of beats to a target pulse width, and makes the target pulse width greater than the pulse width, and runs the target pulse width of the number of beats to generate a drive pulse signal;

[0090] The control module 330 controls the motor to run with the drive pulse signal.

[0091] In one embodiment, the acquisition module 310 can be used to acquire the number of pulses of the motor and the pulse width of each pulse, so as to facilitate subsequent widening processing of the pulse width of the corresponding pulses. The pulse width of the starting pulse and the pulse width of the last pulse affect the stability of the motor during startup and shutdown, respectively, and thus affect the stability of the motor operation. The adjustment module 320 can be used to widen the pulse width of both the starting and last pulses based on the received pulse widths of each pulse, thereby obtaining the target pulse width. The control module 330 can be used to control the motor to operate stably according to the adjusted pulse widths of each pulse.

[0092] The solution in this embodiment improves the motor's operational stability simply by modifying the motor driver program, without altering the motor's structural design. Simultaneously, it ensures that the motor's output torque does not decrease and its speed does not drop significantly, thus avoiding changes to the focusing structure (such as torque and focusing stroke) of the projection lens in the micro-projection device.

[0093] <Controller Implementation Example>

[0094] This application provides a controller, such as... Figure 4As shown, the controller 400 includes a memory 410 and a processor 420; wherein the memory 410 is used to store a computer program, and the processor 420 is used to implement the steps of the motor drive method as described above when executing the computer program.

[0095] The processor 420 can output drive pulse signals, which drive the motor to work via the drive IC.

[0096] The solution in this embodiment improves the motor's operational stability simply by modifying the motor driver program, without altering the motor's structural design. Simultaneously, it ensures that the motor's output torque does not decrease and its speed does not drop significantly, thus avoiding changes to the focusing structure (such as torque and focusing stroke) of the projection lens in the micro-projection device.

[0097] <Example of Micro-projection device>

[0098] This application provides a micro-projection device, such as... Figure 5 As shown, the micro-projection device 500 includes: a projection lens 510, a focusing element 520, a motor 530, and a motor drive device 540, wherein the motor drive device 540 is the motor drive device as described in claim 8; the motor drive device 540 is connected to the motor 530, and the motor 530 is connected to the projection lens 510 through the focusing element 520.

[0099] In the micro-projection device, the projection lens 510 uses a motor 530 to drive the projection lens 520 to move, thereby achieving an automatic focusing function; it also involves a focusing component 520, and the focusing component 502 can be a focusing gear.

[0100] The motor drive device 540 provided in this application embodiment drives the motor 530 to drive the projection lens 510 to achieve automatic focusing. The motor 530 runs stably during operation, the focusing time can meet a certain specified time, and the focusing accuracy is good, which can improve the user's operating experience.

[0101] The specific implementation of the micro-projection device in this application can refer to the above-described motor drive method embodiment. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0102] <Example of Computer-Readable Storage Medium>

[0103] This embodiment provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the motor drive method described above.

[0104] One or more embodiments of this specification may be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this specification.

[0105] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0106] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0107] Computer program instructions used to perform the operations of the embodiments described herein may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of this specification.

[0108] Various aspects of this specification are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0109] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0110] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0111] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this specification. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions. It is well known to those skilled in the art that implementation in hardware, implementation in software, and implementation using a combination of software and hardware are equivalent.

[0112] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0113] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A micro-projection device, characterized in that, The micro-projection device includes: a projection lens (510), a focusing component (520), a stepper motor (530), and a motor drive device (540). The stepper motor (530) includes multiple pulse counts in one cycle, each pulse count corresponding to a set pulse width. The motor drive device (540) includes: The acquisition module (310) acquires the number of steps of the motor and the pulse width of each step, wherein the pulse width of each step is the same; The adjustment module (320) adjusts the pulse width of at least one of the number of beats to a target pulse width, and makes the target pulse width greater than the pulse width, and runs the target pulse width of the number of beats to generate a drive pulse signal; wherein, adjusting the pulse width of at least one of the number of beats to the target pulse width includes any of the following: The pulse width of at least one of the starting beat count and the last beat count is adjusted to the target pulse width; The pulse width of the starting beat count and the pulse width of at least one between the starting beat count and the last beat count are adjusted to the target pulse width; and, The pulse width of the last beat number and the pulse width of at least one between the starting beat number and the last beat number are adjusted to the target pulse width; The motor drive device further includes a control module (330) that controls the stepper motor (530) to run with the drive pulse signal; The motor drive device (540) is connected to the stepper motor (530), and the stepper motor (530) is connected to the projection lens (510) through the focusing component (520).

2. The micro-projection device according to claim 1, characterized in that, The target pulse width is at least twice the pulse width.

3. The micro-projection device according to claim 1, characterized in that, The stepper motor (530) is a four-phase eight-step stepper motor. The pulse width of the first step and the eighth step are both adjusted to the target pulse width, so that the target pulse width is twice the pulse width, and the pulse width of the second to seventh steps remains unchanged, so as to generate the drive pulse signal.

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