CN114545719A

CN114545719A - Automatic focusing device, projection equipment and automatic focusing method

Info

Publication number: CN114545719A
Application number: CN202210164877.9A
Authority: CN
Inventors: 杜世杰; 欧阳剑; 张聪; 胡震宇
Original assignee: Shenzhen Huole Science and Technology Development Co Ltd
Current assignee: Shenzhen Huole Science and Technology Development Co Ltd
Priority date: 2022-02-22
Filing date: 2022-02-22
Publication date: 2022-05-27
Anticipated expiration: 2042-02-22
Also published as: CN114545719B

Abstract

The application discloses an automatic focusing device, projection equipment and an automatic focusing method. The automatic focusing device comprises a focusing lens, a focusing piece, a driving mechanism and a position detection mechanism. The focus lens includes a focus lens barrel and a lens body that is retractable with respect to the focus lens barrel. The driving mechanism is used for driving the focusing piece to rotate so as to drive the lens body to rotate around the optical axis direction and move relative to the focusing lens barrel in the optical axis direction. The position detection mechanism comprises a sliding part, a magnetic part and a magnetic inductor which are linked with the focusing part. The driving mechanism is also used for driving the sliding piece to move along the direction of the optical axis when the focusing piece is driven to rotate. One of the magnetic member and the magnetic sensor is disposed on the slider, and the other is fixedly disposed with respect to the focus adjustment lens barrel. The magnetic inductor is used for detecting the magnetic signal of the magnetic piece in real time so as to acquire the real-time position of the lens body. By adopting the automatic focusing device, the detection range of the magnetic inductor is reduced, and therefore the automatic focusing accuracy and efficiency are improved.

Description

Automatic focusing device, projection equipment and automatic focusing method

Technical Field

The application relates to the technical field of projection, in particular to an automatic focusing device, projection equipment and an automatic focusing method.

Background

The lens of the existing image pickup device or projection device often needs to be adjusted in focal length to obtain a clearer image, and the traditional focusing mode is adjusted by manually screwing the lens, but manual adjustment is inconvenient in many cases, so that the use is inconvenient. With the development of intelligent technology, the focusing mode of automatic focusing is widely applied to intelligent projection products.

The existing automatic focusing structure mostly realizes the transmission of focusing through open-loop stepping motor control. Thus, the open-loop position control is easily out of focus due to the influence of the mass of the transmission gear and the motor. The user can only reach the clear automatic focusing effect again by calibrating the transmission position of the focusing motor again.

Besides the transmission of an open-loop stepping motor, a servo motor capable of achieving accurate position closed-loop control is also available in the market. However, the servo motor generally has the disadvantages of high cost, large volume and the like. In summary, the current projection light chassis focus motor system has no real-time position feedback function.

In the application of the existing micro-projector shell, the driving module usually achieves the telescopic movement of the optical machine shell lens through the matching among the gear, the piece to be focused (such as a lens barrel and the like) and the focusing sleeve, thereby achieving the effect of optical focusing. The current motor module adopts the sensing technology of an optical coupler to judge the rotation angle of a gear so as to judge the current position of the optical shell lens. However, only the positions of the points of the two optocouplers can be read, and the position information of the transmission of the part to be focused and the rotation of the gear in the rotating process is not visible. In addition, due to the gear transmission design of the reduction gearbox and the motor, the stepping motor generally generates a backlash phenomenon in the rotation process. Once the motor rotates to idle or the gear drive is matched with the sliding teeth, a motor driving signal sent by a Micro Control Unit (MCU) for controlling the motor cannot accurately control the focusing position of the rotation direction of the motor.

Because the position information of the transmission of the to-be-focused part and the gear rotation is not visible in the rotating process, in order to avoid the deviation of the focusing position caused by the idle rotation of the motor or the matching of the gear transmission and the sliding teeth, the existing automatic focusing technology completely returns the gear to the position of the starting point optical coupler, and then pushes the motor and the gear to rotate to the position of the to-be-focused part with clear focusing in the forward direction, so that the automatic focusing time is too long. For such a situation, a magnetic induction structure is usually introduced into the automatic focusing device to obtain the lens position, but the transmission stroke and/or the rotation angle of the general design is large, so that the detection range of the sensor is too large, and the focusing efficiency and precision are affected.

Disclosure of Invention

In view of this, the present application provides an automatic focusing apparatus, a projection device and an automatic focusing method to solve the problem that the detection range of the sensor is too large.

In a first aspect, an embodiment of the present application provides an autofocus apparatus, including:

the focusing lens comprises a focusing lens barrel and a lens body which is telescopic relative to the focusing lens barrel;

the focusing piece is connected with the lens body in a matched manner;

the driving mechanism is used for driving the focusing piece to rotate so as to drive the lens body to rotate around the optical axis direction and simultaneously move relative to the focusing lens barrel in the optical axis direction;

a position detection mechanism electrically connected to the drive mechanism, the position detection mechanism comprising:

a slider that is linked with the focus adjustment member; the driving mechanism is also used for driving the sliding piece to move along the optical axis direction when driving the focusing piece to rotate;

a magnetic member;

and one of the magnetic part and the magnetic inductor is arranged on the sliding part, the other one of the magnetic part and the magnetic inductor is fixedly arranged relative to the focusing lens barrel, and the magnetic inductor is used for detecting the magnetic signal of the magnetic part in real time so as to acquire the real-time position of the lens body.

In some embodiments, the driving mechanism includes a bracket fixedly disposed on the focus lens barrel, and the slider is slidably disposed between the bracket and the focus lens barrel.

In some embodiments, the bracket defines a guide groove, the sliding member is slidably received in the guide groove, and an extending direction of the guide groove is parallel to the optical axis direction.

In some embodiments, a side of the sliding member facing away from the bracket is provided with a plurality of guide sliding strips arranged at intervals, and an extending direction of the plurality of guide sliding strips is parallel to the optical axis direction.

In some embodiments, the bracket is provided with a position-avoiding hole at a position corresponding to the magnetic part, and the magnetic part moves in the position-avoiding hole along with the sliding part; alternatively, the first and second electrodes may be,

in the orthographic projection direction perpendicular to the optical axis direction, the orthographic projection of the magnetic part is positioned outside the orthographic projection of the bracket.

In some embodiments, the focusing lens barrel is provided with a spiral groove; the focusing piece can slide along the spiral groove and drive the lens body to rotate around the optical axis direction and move relative to the focusing lens barrel in the optical axis direction, and the sliding piece is driven to move in the optical axis direction.

In some embodiments, the driving mechanism further comprises a driving motor fixed on the bracket and a gear arranged at the output end of the driving motor; the focusing piece comprises a focusing rack meshed with the gear and a transmission piece in sliding fit with the spiral groove; one end of the transmission piece is fixed on the lens body, and the other end of the transmission piece penetrates through the sliding piece and is fixed on the focusing rack; the gear is used for driving the focusing rack and the transmission piece to rotate around the direction of the optical axis.

In some embodiments, the sliding member defines a driving groove for the transmission member to pass through, and an extending direction of the driving groove is different from an extending direction of the spiral groove.

In some embodiments, the driving groove is elongated, and the transmission member abuts against the sliding member in the groove width direction to slide relative to the sliding member in the groove length direction.

In some embodiments, the focus rack is movably disposed on the mount and/or the slider.

In some embodiments, the focusing rack includes an engaging portion engaged with the gear and two connecting portions disposed on opposite sides of the engaging portion along the optical axis direction, and the bracket is provided with a limiting portion slidably engaged with the two connecting portions.

In some embodiments, the limit part and the bracket and/or the sliding part jointly enclose a limit space, and the focus rack can move in the limit space.

In some embodiments, the position-limiting part comprises a first position-limiting part and a second position-limiting part which are oppositely arranged, and a gap for the engagement part to pass through is formed between the first position-limiting part and the second position-limiting part;

in the optical axis direction, the size of the gap is larger than that of the engaging portion, and the extending direction of the gap is perpendicular to the optical axis direction; alternatively, in the optical axis direction, the size of the gap is equal to the size of the engaging portion, and the extending direction of the gap is parallel to the extending direction of the spiral groove.

In some embodiments, the lens body includes a first lens and a second lens, the first lens is fixedly disposed relative to the second lens in the optical axis direction, and the first lens is rotatably disposed relative to the second lens in a circumferential direction perpendicular to the optical axis direction; the focusing piece is fixedly connected with the first lens, and the sliding piece is arranged on the focusing lens barrel in a sliding mode and is fixedly connected with the second lens.

In some embodiments, the rotation of the focusing element can drive the first lens to rotate around the optical axis direction while moving relative to the focus lens barrel in the optical axis direction, and can drive the sliding element to move in the optical axis direction, so as to limit the second lens to move relative to the focus lens barrel only in the optical axis direction.

In some embodiments, the focusing lens barrel is provided with a sliding guide slot in sliding fit with the sliding member, and an extending direction of the sliding guide slot is parallel to the optical axis direction.

In some embodiments, the magnetic member is disposed at an end of the sliding member facing away from the lens body.

In some embodiments, the autofocus device further includes a circuit board fixed to the mount or the focus lens barrel; the magnetic inductor is arranged on the circuit board and is positioned in the magnetic field range of the magnetic piece.

In a second aspect, an embodiment of the present application provides a projection apparatus, which includes an optical chassis and the above-mentioned automatic focusing device, where the automatic focusing device is disposed on the optical chassis and is used for focusing the optical chassis to adjust the definition of an image.

In a third aspect, an embodiment of the present application provides an automatic focusing method, where the method is applied to the projection apparatus; the method comprises the following steps:

acquiring a defocusing parameter of the lens body;

when the defocusing parameters meet preset conditions, detecting a first magnetic signal corresponding to the current position of the magnetic piece through the magnetic inductor;

calculating focusing parameters of the lens body with clear focusing according to the defocusing parameters and the first magnetic signals; the focusing parameters comprise a target position of the magnetic piece when the lens body is in clear focusing;

controlling the driving mechanism to drive the focusing piece to rotate according to the focusing parameters so as to drive the lens body to rotate around the optical axis direction, move relative to the focusing lens barrel in the optical axis direction and drive the sliding piece to move in the optical axis direction;

and when the magnetic inductor detects a second magnetic signal corresponding to the target position of the magnetic piece, finishing focusing.

The automatic focusing device comprises a focusing lens, a focusing mechanism and a position detection mechanism, and is designed based on linkage matching of a focusing piece, a driving mechanism and a sliding piece, so that when the focusing piece rotates, a lens body is driven to move relative to a focusing lens barrel in the optical axis direction while rotating around the optical axis direction, and the sliding piece is driven to move along the optical axis direction. So, the magnetic inductor can be through detecting the magnetic signal that sets up the magnetic part on the slider to acquire the real-time position of magnetic part, because slider and camera lens body are followed linear motion that the optical axis direction was done is the same, thereby can acquire the real-time position of camera lens body fast, not only reduce the detection scope of magnetic inductor, simplify the structure, and improved autofocus's precision and efficiency.

Drawings

Fig. 1 is a schematic diagram of modules of a projection apparatus provided in an embodiment of the present application.

Fig. 2 is a schematic structural diagram of an autofocus apparatus according to a first embodiment of the present application.

Fig. 3 is an exploded view of the autofocus device of fig. 2.

Fig. 4 is a schematic view of another view angle of the autofocus apparatus of fig. 3.

Fig. 5 is an exploded view of a partial structure of the autofocus apparatus of fig. 4.

Fig. 6 is a schematic diagram of another view angle of a partial structure of the autofocus apparatus in fig. 5.

Fig. 7 is a schematic view of another view angle of the autofocus apparatus of fig. 2.

Fig. 8 is a cross-sectional view of the autofocus apparatus of fig. 7 taken along line a-a.

Fig. 9 is a cross-sectional view of the autofocus apparatus of fig. 7 taken along line B-B.

Fig. 10 is another exploded view of the autofocus device of fig. 2.

Fig. 11 is a schematic structural diagram of an autofocus apparatus according to a second embodiment of the present application.

Fig. 12 is an exploded view of the autofocus device of fig. 11.

Fig. 13 is a cross-sectional view of the autofocus apparatus of fig. 11.

Fig. 14 is a flowchart of an autofocus method according to an embodiment of the present application.

Description of the main elements

Projection device 1000

Automatic focusing

device

1, 1a

Locking part 10

Optical case 2

Control module 3

Power supply module 4

Focus lens 100

Focusing lens barrels 101, 101a

Locking hole 1020

Locking hole 1011

Helical groove 1012

Guide chute 1013

Lens bodies

102, 102a

First lens 1021

Second lens 1022

Optical lens group 103

Mounting plate 104

Focusing member 200

Focusing rack 21

Meshing surface 2101

Sliding guide surface 2102

Connection hole 211

Transmission element 22

First connection section 221

Guide section 222

Second connecting section 223

Engaging part 25

Connecting part 26

Stopper 40

Spacing space 401

First position-limiting part 41

The second position-limiting portion 42

Gap 43

Driving mechanism 300

Support 30

Through

holes

301, 602

Guide groove 302

Avoiding hole 303

Guide hole 304

First frame body 31

Positioning post 311

Second frame 32

Drive motor 51

Mounting block 511

Gear 52

Position detection mechanism 400

Slide

61, 61a

Driving groove 601

Holding groove 603

Slide bar 611

Mounting part 613

Stopping part 614

Magnetic member 62

Magnetic inductor 63

Circuit board 500

Positioning hole 501

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

The terms "first," "second," and the like in the description and claims of the present application and in the foregoing drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential order. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "comprises" and any variations thereof is intended to cover non-exclusive inclusions. Further, the present application may be embodied in many different forms and is not limited to the embodiments described in the present embodiment. The following detailed description is provided for the purpose of providing a more thorough understanding of the present disclosure, and the words used to indicate orientation above, below, left and right are used solely to describe the illustrated structure in the context of the corresponding figures. The term "optical axis direction" refers to a direction parallel to the central axis of the automatic focus lens 100.

While the specification concludes with claims describing preferred embodiments of the present application, it is to be understood that the above description is made only for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The protection scope of the present application shall be subject to the definitions of the appended claims.

Referring to fig. 1 and fig. 2, fig. 1 is a schematic diagram of modules of a projection apparatus 1000 according to an embodiment of the present application, and fig. 2 is a schematic structural diagram of an autofocus device 1 according to a first embodiment of the present application. The projection apparatus 1000 includes an autofocus device 1 and an optical chassis 2. The autofocus apparatus 1 is mounted on the optical housing 2.

The projection apparatus 1000 may be an electronic apparatus having a projection function such as a projector, or the like. The projection apparatus 1000 further includes a control module 3 and a power module 4 electrically connected to the automatic focusing apparatus 1 and the optical chassis 2. The power module 4 provides electric energy for the automatic focusing device 1, the optical machine housing 2 and the control module 3 to work. The control module 3 can intelligently control the automatic focusing device 1 to perform focusing. The control module 3 of the projection apparatus 1000 includes a main control circuit board, and the circuit board of the automatic focusing apparatus 1 may be used as the main control circuit board or an auxiliary circuit board electrically connected to the main control circuit board. By adding the automatic focusing device 1 provided by the application into the projection equipment 1000, the projection equipment 1000 can focus more quickly and clearly, and the user experience is better.

It should be understood by those skilled in the art that fig. 1 is only an example of the projection device 1000 and does not constitute a limitation of the projection device 1000, and that the projection device 1000 may include more or less components than those shown in fig. 1, or some components may be combined, or different components, for example, the projection device 1000 may also include, but is not limited to, a communication system, memory, etc.

Referring to fig. 2 to 3, the automatic focusing apparatus 1 includes a focusing lens 100, a focusing element 200, a driving mechanism 300, and a position detecting mechanism 400. The focus lens 100 includes a focus lens barrel 101 and a lens body 102 that is retractable with respect to the focus lens barrel 101. The automatic focusing apparatus 1 is used to focus the focusing lens 100 to adjust the sharpness of an image. The focus lens barrel 101 is sleeved outside the lens body 102, and the lens body 102 is movably inserted into the focus lens barrel 101, so that the lens body 102 can move along the optical axis direction relative to the focus lens barrel 101 and can rotate around the optical axis direction.

Referring to fig. 1 to 4, in the present embodiment, a focus lens 100 is mounted on an optical housing 2 through a focus lens barrel 101. The lens body 102 further has an optical lens group 103 mounted therein. The focusing lens 100 further includes a spacer, a locking ring, a sealing ring, etc. to mount each optical lens of the optical lens group 103 in the lens body 102 through these components. It is understood that in some embodiments, some lenses of the optical lens group 103 may also be mounted in the focusing lens barrel 101, and certainly, there are some other arrangements of the optical lens group 103, which can be modified by those skilled in the art according to the type of the focusing lens 100, and thus, the description is not repeated here. The focusing lens barrel 101 is further provided with a mounting plate 104, and the focusing lens barrel 101 is mounted on the optical housing 2 through the mounting plate 104, so that the focusing lens barrel is convenient to mount and dismount.

The focusing member 200 is coupled to the lens body 102. The driving mechanism 300 is configured to drive the focusing element 200 to rotate, so as to drive the lens body 102 to rotate around the optical axis direction and move relative to the focusing barrel 101 in the optical axis direction. The position detection mechanism 400 is electrically connected to the drive mechanism 300. The position detection mechanism 400 includes a slider 61, a magnetic member 62, and a magnetic sensor 63. The slider 61 is linked with the focusing member 200. The driving mechanism 300 is also used for driving the slider 61 to move in the optical axis direction when the focusing member 200 is driven to rotate. The magnetic sensor 63 is used for detecting the magnetic signal of the magnetic member 62 in real time to obtain the real-time position of the lens body 102. In some embodiments, the magnetic member 62 is provided on the slider 61, and the magnetic sensor 63 is fixedly provided with respect to the focus lens barrel 101. In other embodiments, the magnetic sensor 63 is disposed on the slider 61, and the magnetic member 62 is fixedly disposed with respect to the focus adjustment lens barrel 101. Next, a detailed description will be given of an example in which the magnetic material 62 is provided on the slider 61 and the magnetic sensor 63 is fixed to the focus lens barrel 101. The magnetic sensor 63 is disposed on the sliding member 61, and the specific arrangement manner of the magnetic member 62 fixed to the focus adjustment lens barrel 101 can refer to the following description of the specific embodiment, which is not repeated herein.

The automatic focusing device 1 provided by the application is designed by linkage matching of the focusing piece 200, the driving mechanism 300 and the sliding piece 61, so that when the focusing piece 200 rotates, the lens body 102 is driven to move relative to the focusing lens barrel 101 in the optical axis direction while rotating around the optical axis direction, and the sliding piece 61 is driven to move along the optical axis direction. Like this, magnetic inductor 63 can be through detecting the magnetic signal that sets up magnetic part 62 on slider 61 to acquire the real-time position of magnetic part 62, because slider 61 is the same with the linear motion that lens body 102 was done along the optical axis direction, thereby can be based on the real-time position of the magnetic part 62 who acquires, obtain the real-time position of lens body 102 fast, not only reduce magnetic inductor 63's detection range, simplify the structure, and improved autofocus's precision and efficiency.

In this embodiment, the movement direction of the lens body 102 intersects with the optical axis direction, that is, the lens body 102 performs a spiral movement with the optical axis as an axis, so that the lens body 102 moves relative to the focusing lens barrel 101 in the optical axis direction while rotating around the optical axis direction, thereby realizing the relative displacement between the lens group installed in the lens body 102 and the lens group in the focusing lens barrel 101, and realizing the focusing. The movement direction of the sliding member 61 is parallel to the optical axis direction, and the lens body 102 also makes a linear movement along the optical axis direction, so that the axial movement distance of the lens body 102 can be obtained through the detected linear movement distance (i.e. the axial movement distance) of the sliding member 61 along the optical axis direction, thereby reducing the detection range of the magnetic inductor 63, reducing the operation difficulty, and further improving the accuracy and efficiency of automatic focusing.

The driving mechanism 300 includes a holder 30 fixedly provided on the focus lens barrel 101. The holder 30 may be fixed to the focus lens barrel 101 by, but not limited to, welding, bonding, snapping, screw locking structure, or the like. In the present embodiment, the holder 30 is fixedly provided on the outer side wall of the focus lens barrel 101. Specifically, the focusing lens further includes a plurality of locking members 10, a plurality of locking holes 1011 are formed in the outer side wall of the focusing lens barrel 101, a plurality of through holes 301 are formed in positions of the bracket 30 corresponding to the plurality of locking holes 1011, and the plurality of locking members 10 penetrate through each through hole 301 and are locked in the corresponding locking holes 1011, so that the focusing lens barrel 101 is fixedly connected to the bracket 30. In some embodiments, the bracket 30 may be embedded in the focus lens barrel 101, or fixed to the optical chassis 2 of the auto-focusing apparatus 1 independently of the focus lens barrel 101. Optionally, a fool-proof post is disposed on the bracket 30, and a fool-proof hole matched with the fool-proof post is formed in the focusing lens barrel 101, so as to improve the assembling efficiency.

Referring to fig. 5 and 6 together, specifically, the holder 30 includes a first holder 31 fixed to the focus lens barrel 101 and a second holder 32 connected to the first holder 31. The second frame 32 extends in a direction different from that of the first frame 31, and is used to mount the driving mechanism 300. The first frame 31 is arc-shaped and matches with the focusing lens barrel 101 to improve the connection stability between the first frame 31 and the focusing lens barrel 101. The locking members 10 are mounted at four corners of the first frame 31 to prevent the locking members 10 from interfering with the movement of the slider 61 and/or the focus adjusting member 200.

In the present embodiment, the slider 61 is slidably disposed between the holder 30 and the focus lens barrel 101. Optionally, the bracket 30 is provided with a guide groove 302, the sliding member 61 is slidably accommodated in the guide groove 302, and the extending direction of the guide groove 302 is parallel to the optical axis direction, so as to ensure that the sliding member 61 moves linearly along the optical axis direction. Specifically, the first frame body 31 is recessed toward the side wall of the focus lens barrel 101 to form a guide groove 302. The guide groove 302 is disposed in an area surrounded by the plurality of through holes 301, and is disposed to be staggered from the plurality of through holes 301, so as to prevent the locking member 10 from interfering with the linear movement of the sliding member 61 in the optical axis direction.

Optionally, a side of the sliding member 61 facing away from the bracket 30 is provided with a plurality of guiding sliding bars 611 arranged at intervals. The extending direction of the plurality of guiding and sliding bars 611 is parallel to the optical axis direction. In this way, the contact area between the slider 61 and the focus lens barrel 101 is greatly reduced, so that the friction force between the slider 61 and the focus lens barrel 101 is reduced, and the slider 61 can slide more smoothly in the guide groove 302, so as to better realize the axial sliding of the lens body 102.

In this embodiment, the magnetic element 62 is disposed at an end of the sliding element 61 away from the lens body 102, so as to expand a magnetic field range of the magnetic element 62, and facilitate the magnetic sensor 63 to sense a magnetic signal of the magnetic element 62. Specifically, the position of the bracket 30 corresponding to the magnetic member 62 is provided with a clearance hole 303, and the magnetic member 62 moves in the clearance hole 303 along with the sliding member 61, so that the magnetic member 62 is exposed relative to the bracket 30, the magnetic sensor 63 detects a magnetic signal generated by the magnetic member 62, and the automatic focusing device 1 has a more compact overall structure and is suitable for miniaturization design. Specifically, one side of the first frame 31 facing away from the second frame 32 is provided with an avoiding hole 303 avoiding the magnetic member 62. The clearance hole 303 communicates with the guide groove 302, so that the magnetic member 62 can be retained in the clearance hole 303 by passing through the guide groove 302.

In some embodiments, the magnetic member 62 is disposed close to the bracket 30, and the magnetic member 62 is located outside a coverage area of the bracket 30 along a direction perpendicular to the optical axis, in other words, in an orthogonal projection direction along the direction perpendicular to the optical axis, an orthogonal projection of the magnetic member 62 is located outside an orthogonal projection of the bracket 30, so as to avoid forming an avoiding hole 303 on the bracket 30 for avoiding the magnetic member 62, thereby simplifying the processing process of the bracket 30.

Wherein the magnetic member 62 has a magnetic field. Magnetic part 62 accessible viscose, threaded connection, joint, crimping etc. form are fixed on slider 61 to make magnetic part 62 and slider 61 be linear motion in step along the optical axis direction, thereby reduced the detection scope of magnetic inductor, and promoted the precision and the speed that detect. Optionally, the sliding member 61 is provided with a receiving groove (not shown) for receiving the magnetic member 62, so as to facilitate assembly, and the contact area between the sliding member 61 and the magnetic member 62 is increased, thereby improving the connection reliability and stability between the sliding member 61 and the magnetic member 62. Specifically, the magnetic member 62 moves with the movement of the slider 61, and the magnetic sensor 63 can calculate the linear movement distance of the magnetic member 62 from the magnetic signal intensity of the magnetic member 62. The linear movement distance can be converted into a rotation angle of the lens body 102 and a movement distance of the lens body 102 in the optical axis direction. This application is through setting up magnetism spare 62 and magnetic inductor 63, and magnetic inductor 63 obtains the rectilinear movement distance of slider 61 in real time through the magnetic field variation of magnetism spare 62 to in the real-time position of waiting to focus piece 200 is obtained to quick and accurate. Thus, even if the driving mechanism 300 rotates to perform idle rotation or the gear transmission of the driving mechanism 300 is matched with the focusing element 200, because the motion state of the lens body 102 can be monitored by the magnetic inductor 63 in real time, there is no deviation of a focusing position (the deviation between the actual position of the focusing element 200 driven by the driving mechanism 300 and the calculated preset position), thereby avoiding uncontrollable factors caused by the rotating idle rotation or the gear transmission matching condition of the driving motor in the optical coupling focusing scheme of the prior art, and having high focusing precision. In addition, this application sets up single magnetic part 62 on slider 61 to realize that magnetic inductor 63 can obtain the real-time position of lens body 102 through the magnetic signal of the single magnetic part 62 of response, simplified the operation complexity, and reduced the volume of magnetic part 62, compressed design cost, thereby it is great to avoid current a plurality of magnetic part annular settings and appear transmission stroke/angle, need use between multipolar magnetic part and the magnetic inductor to do complicated algorithm and the problem that the magnetic pole matches.

The magnetic sensor 63 is used for determining the relative position of the magnetic member 62 according to the sensed magnetic signal intensity of the magnetic member 62, so as to obtain the rotation angle and the movement distance along the optical axis direction of the sliding member 61 and the lens body 102. Specifically, the magnetic member 62 and the magnetic sensor 63 are disposed at an interval in a direction perpendicular to the optical axis, so as to avoid interference between the magnetic member 62 and the magnetic sensor 63.

The magnetic member 62 includes, but is not limited to, at least one of a magnet and a magnetic alloy member. The magnetic sensors 63 include, but are not limited to, one or more of linear tunneling magneto-resistive sensors, linear hall sensors, anisotropic magneto-resistive sensors, and giant magneto-resistive sensors. It can be understood that the above sensors can be matched with the magnetic element 62 to achieve a better sensing effect, which is beneficial to accurate focusing. Among them, the magnetic sensor 63 is preferably a linear tunnel magnetoresistive sensor and a linear hall sensor. The linear tunnel magnetoresistive sensor and the linear hall sensor both map the change in the linear distance of the magnetic member 62 with respect to the sensor by the change in the magnetic flux density, and obtain the rotation angle information by conversion.

Optionally, in some embodiments, autofocus device 1 further comprises circuit board 500. The magnetic inductor 63 is disposed on the circuit board 500 and is located within the magnetic field of the magnetic member 62. The circuit board 500 is fixed to the holder 30 or the focus lens barrel 101. The circuit board 500 may be fixed to the first frame 31 and the focus lens barrel 101 by welding, bonding, crimping, snapping, or a screw locking structure. Specifically, in the present embodiment, the Circuit Board 500 is a Printed Circuit Board (PCB) fixed on the first frame 31. The magnetic inductor 63 faces the avoiding hole 303. Optionally, the circuit board 500 faces the avoiding hole 303, so that the magnetic sensor 63 disposed on the circuit board 500 is located in the avoiding hole 303, so as to ensure that the magnetic sensor 63 can always sense the magnetic signal intensity of the magnetic member 62, and avoid the problem that the magnetic member 62 and the magnetic sensor 63 are contaminated by external impurities or damaged by collision of other elements, which may occur to the magnetic member 62 and/or the magnetic sensor 63.

Optionally, the first frame 31 is provided with a positioning column 311 protruding around the avoiding hole 303, and the circuit board 500 is provided with a positioning hole 501 matching with the positioning column 311, so that the circuit board 500 is convenient to mount. The positioning post 311 and the positioning hole 501 can also be configured as a matching groove or bump structure.

In some embodiments, the circuit board 500 may also be fixed on the focus sleeve 101. The magnetic sensor 63 on the circuit board 500 can also be located outside the avoiding hole 303. It should be noted that the installation position of the circuit board 500 is not specifically limited in this application, as long as the magnetic sensor 63 can sense the magnetic strength of the magnetic member 62.

It is understood that the circuit board 500 may be an MCU, a Microprocessor (MPU), a System On Chip (SOC), and the like. After the circuit board 500 determines the current position of the lens body 102 according to the motion state of the magnetic member 62 acquired by the magnetic sensor 63, the current for performing corresponding positive or negative compensation on the control current of the driving mechanism 300 controls the driving mechanism 300 to drive in the forward direction or in the reverse direction, so that the driving mechanism 300 drives the focusing member 200 to move to the preset position. The preset positions can be set according to the application scene of the position detection mechanism 400, and the motion states (rotation angles and/or translation distances) of different lens bodies 102 corresponding to different preset positions calibrated according to the definition determination are prestored in the program of the circuit board 500, so that the speed of feedback control of the circuit board 500 can be increased, and the focusing time can be further shortened.

Referring to fig. 1 to 6 again, in the present embodiment, the focusing lens barrel 101 is provided with a spiral groove 1012. The focusing member 200 can slide along the spiral groove 1012 and drive the lens body 102 to rotate around the optical axis direction and move in the optical axis direction relative to the focusing barrel 101, and drive the sliding member 61 to move in the optical axis direction. The spiral groove 1012 extends spirally around the optical axis direction of the focus lens barrel 101, i.e., the extending direction of the spiral groove 1012 intersects with the optical axis direction and a radial direction perpendicular to the optical axis direction. The spiral groove 1012 is a through groove provided on the focus lens barrel 101. In this way, when the driving mechanism 300 drives the focusing member 200 to slide along the spiral groove 1012, the rotation of the focusing member 200 is converted into the rotation and linear motion of the lens body 102, so that the lens body 102 can rotate around the optical axis direction and can move relative to the focusing lens barrel 101 along the optical axis direction, thereby reducing the sensing range of the magnetic sensor 63.

The driving mechanism 300 further includes a driving motor 51 fixed to the bracket 30 and a gear 52 provided at an output end of the driving motor 51. The drive motor 51 is preferably a stepper motor. Specifically, the driving motor 51 is provided with a mounting block 511, and the driving motor 51 is fixed to the second frame body 32 through the mounting block 511.

The focusing member 200 includes a focusing rack 21 engaged with the gear 52 and a transmission member 22 slidably engaged with the spiral groove 1012. One end of the transmission member 22 is fixed to the lens body 102. The other end of the transmission member 22 passes through the slider 61 and is fixed to the focus rack 21. The gear 52 is used for driving the focusing rack 21 and the transmission member 22 to rotate around the optical axis direction.

Referring to fig. 7 to 9, in particular, the transmission member 22 is a cylindrical member with a step structure, and includes a first connection section 221, a guide section 222 and a second connection section 223 connected in sequence. The first connecting section 221 is fixedly connected with the lens body 102, the guiding section 222 is in sliding fit with the spiral groove 1012, and the second connecting section 223 is fixedly connected with the focusing rack 21. The connection between the transmission member 22 and the lens body 102 and the focusing rack 21 can be performed by a screw connection, a riveting, a clamping, etc. For convenience of assembly and processing, the first connecting section 221 is in threaded connection with the lens body 102, and the second connecting section 223 is in plug-in connection with a connecting hole 211 formed in the focusing rack 21.

Referring to fig. 2 to 10, in the embodiment, the sliding member 61 is provided with a driving groove 601 for the transmission member 22 to pass through, and the extending direction of the driving groove 601 is different from the extending direction of the spiral groove 1012, so that the transmission member 22 generates a force on the sliding member 61 in the optical axis direction, and the sliding member 61 can move only along the optical axis direction under the limiting action of the guiding groove 302.

Alternatively, the driving groove 601 is elongated, and the transmission member 22 abuts against the sliding member 61 in the groove width direction to slide relative to the sliding member 61 in the groove length direction, so that the transmission member 22 can drive the sliding member 61 to slide in the groove width direction. Note that the groove width direction is parallel to the optical axis direction, and the groove length direction is perpendicular to the optical axis direction.

Specifically, the groove length of the driving groove 601 is greater than the groove width of the driving groove 601, and the radial dimension of the transmission member 22 (i.e., the second connecting section 223) accommodated in the driving groove 601 is equal to the groove width of the driving groove 601 and less than the groove length of the driving groove 601; here, the groove length of the driving groove 601 means the length of the long side of the axial cross section of the driving groove 601, and the groove width of the driving groove 601 means the length of the short side of the axial cross section of the driving groove 601.

The focus rack 21 is movably arranged on the holder 30 and/or the slider 61. In the present embodiment, the focus rack 21 is movably provided on the mount 30. Specifically, the focus rack 21 includes an engaging portion 25 engaged with the gear 52 and two connecting portions 26 disposed on opposite sides of the engaging portion 25 in the optical axis direction, and the holder 30 is provided with a stopper portion 40 slidably fitted to the two connecting portions 26. The limiting portion 40 and the bracket 30 and/or the slider 61 together enclose a limiting space 401, and the focus rack 21 can move in the limiting space 401, so that the lens body 102 can better rotate relative to the focus lens barrel 101 in the optical axis direction.

Specifically, the limiting portion 40 includes a first limiting portion 41 and a second limiting portion 42 that are disposed opposite to each other, and a gap 43 through which the engaging portion 25 passes is formed between the first limiting portion 41 and the second limiting portion 42. In the optical axis direction, the size of the gap 43 is larger than that of the engaging portion 25, and the extending direction of the gap 43 is perpendicular to the optical axis direction; alternatively, the dimension of the gap 43 is equal to the dimension of the engaging portion 25 in the optical axis direction, and the extending direction of the gap 43 is parallel to the extending direction of the spiral groove 1012.

In the present embodiment, the first position-limiting portion 41 is disposed on the first frame 31, and the second position-limiting portion 42 is disposed on the second frame 32. The focus rack 21 includes an engagement surface 2101 engaged with the gear 52 and a slide guide surface 2102 disposed opposite to the engagement surface 2101. The sliding guide surface 2102 is a smooth and continuous curved surface to improve the smoothness of the rotation of the focus rack 21 along the spiral groove 1012. Optionally, a guide hole 304 is formed in a position of the first frame body 31 corresponding to the focus rack 21, and the sliding guide surface 2102 of the focus rack 21 is attached to the exposed surface of the sliding member 61 relative to the guide hole 304, so that the focus rack 21 drives the sliding member 61 to move along the optical axis direction. Alternatively, the sliding guide surface 2102 and the surface of the first frame body 31 abutting against the focus rack 21 and the surface of the slider 61 facing the first frame body 31 are slidably engaged, so that the friction force between the focus rack 21 and the first frame body 31 and the slider 61 is reduced, and the focus rack 21 can rotate along the spiral groove 1012 more smoothly.

When the automatic focusing apparatus 1 is used for focusing, the driving motor 51 is operated to drive the gear 52 to rotate, and the rotation of the gear 52 drives the focusing rack 21 to rotate, so that the transmission member 22 connected to the focusing rack 21 slides along the spiral groove 1012, that is, the transmission member 22 and the focusing rack 21 rotate around the optical axis direction. At this time, when the transmission member 22 rotates relative to the focus adjustment barrel 101, there is a translational motion component along the optical axis direction, and the translational motion component can drive the sliding member 61 and the lens body 102 to move along the optical axis direction. Specifically, the transmission member 22 rotates around the optical axis direction after receiving the moment transmitted by the driving motor 51 and rotates around the optical axis direction, and at the same time, the transmission member is limited by the spiral groove 1012 on the focus lens barrel 101, and generates a translation along the optical axis direction. In addition, since the sliding member 61 is engaged with the edge of the transmission member 22 through the elongated driving groove 601 opened thereon, that is, the transmission member 22 abuts against the sliding member 61 in the groove width direction to slide relative to the sliding member 61 in the groove length direction, the rotational movement of the transmission member 22 about the optical axis direction does not cause the rotation of the sliding member 61 but causes the movement of the sliding member 61 in the optical axis direction. In other words, since the driving groove 601 and the transmission member 22 have a clearance in the direction perpendicular to the optical axis, the rotation of the transmission member 22 does not cause the rotation of the slider 61, but since the driving groove 601 and the transmission member 22 have no clearance in the optical axis direction, that is, the driving groove 601 of the slider 61 abuts against the transmission member 22 in the optical axis direction, the rotation of the transmission member 22 causes the movement of the slider 61 in the optical axis direction. A signal related to the focus position of the lens body 102 is transmitted to a magnetic sensor 63 fixed to the circuit board 500 through a magnetic member 62 fixed relative to the slider 61. Since the magnetic sensor 63 is fixed on the circuit board 500, and the circuit board 500 is fixed on the bracket 30 and is stationary relative to the focusing barrel 101, the real-time position of the magnetic member 62 can be quickly calculated by sensing the magnetic signal of the magnetic member 62, so as to obtain the focusing position of the lens body 102. In addition, since the magnetic member 62 moves linearly along the optical axis direction only along with the slider 61, the calculation of the magnetic signal of the magnetic member 62 sensed by the magnetic sensor 63 is simplified, thereby reducing the difficulty of the calculation and further improving the focusing accuracy and speed of the automatic focusing apparatus 1.

Referring to fig. 1, 11 to 13 together, in the second embodiment, the structure of the autofocus apparatus 1a is similar to that of the autofocus apparatus 1 in the first embodiment. In contrast, the structure and arrangement of the slider 61a in the second embodiment are different from those of the slider 61 in the first embodiment.

It is understood that during the focusing process, the optical lens assembly in the lens body rotates along with the rotation of the focusing element 200. Because the lens real object is not in a perfect circular scanning shape, the lens assembly rotates relative to the lens body to automatically adjust the optical effect of the device. In the present application, the lens body 102a is configured with a plurality of lens elements, so as to prevent the optical effect from changing due to the rotation of the optical lens assembly. Specifically, in the present embodiment, the lens body 102a includes a first lens 1021 and a second lens 1022 connected to the first lens 1021. The first lens 1021 is fixed relative to the second lens 1022 in the optical axis direction, and the first lens 1021 is rotationally arranged relative to the second lens 1022 in the circumferential direction perpendicular to the optical axis direction. The focus adjusting member is fixedly connected to the first lens 1021, and the slider 61a is slidably disposed on the focus lens barrel 101a and fixedly connected to the second lens 1022. It should be noted that the lens elements included in the lens body 102a may also include more than 2 lens elements, and the present application is not particularly limited.

In this embodiment, the movement direction of the first lens 1021 is intersected with the optical axis direction, that is, the first lens 1021 performs a spiral movement with the optical axis as an axis, so that the first lens 1021 rotates around the optical axis direction and moves relative to the focus lens barrel 101a in the optical axis direction, the movement directions of the second lens 1022 and the slider 61a are both parallel to the optical axis direction, that is, the second lens 1022 and the slider 61a perform a linear movement in the optical axis direction, thereby preventing the optical lens assembly installed in the second lens 1022 from rotating, further ensuring that the optical lens assembly of the auto-focus apparatus 1a has a better optical effect before and after focusing, and realizing a relative displacement between the lens assembly installed in the first lens 1021 and the lens assembly in the second lens 1022, thereby realizing focusing.

The first lens 1021 and the second lens 1022 are coaxially disposed. The first lens 1021 is provided with a limit structure along the circumferential direction, the second lens 1022 is provided with a matching structure matched with the limit structure along the circumferential direction, so that the second lens 1022 is limited to be fixedly arranged relative to the first lens 1021 in the optical axis direction, and is rotatably arranged relative to the second lens 1022 in the circumferential direction perpendicular to the optical axis direction, and therefore the first lens 1021 and the second lens 1022 synchronously move linearly along the optical axis direction. The limiting structure and the matching structure can be closed-loop structures or open-loop structures.

Alternatively, the focus lens barrel 101a is provided with a slide guide 1013 slidably engaged with the slider 61, the extension direction of the slide guide 1013 is parallel to the optical axis direction, and thus, when the driving mechanism drives the focusing piece to rotate, the focusing piece drives the first lens 1021 to rotate around the optical axis direction, moves relative to the focus lens barrel 101a in the optical axis direction, and since the second lens 1022 is fixedly disposed relative to the second lens 1022 in the optical axis direction, and is rotatably disposed relative to the second lens 1022 in a circumferential direction perpendicular to the optical axis direction, therefore, the first lens 1021 can drive the second lens 1022 to slide along the guiding-sliding slot 1013, that is, the second lens 1022 can only move in the optical axis direction relative to the focus adjustment barrel 101a, so that the lens group installed in the second lens 1022 will not rotate relative to the second lens 1022, thereby ensuring that the autofocus apparatus 1a has good optical effect after focusing.

The spiral groove 1012 is spaced from the guide groove 1013, and the extending direction of the spiral groove 1012 is different from, i.e. intersects, the extending direction of the guide groove 1013. Alternatively, the extension direction of the guide groove 1013 is located at the middle of the spiral groove 1012, thereby ensuring smoother movement of the first lens 1021 and the second lens 1022. The number of the spiral groove 1012 and the guide groove 1013 may be one or more. The plurality of spiral grooves 1012 and the guide groove 1013 are symmetrically arranged from the central axis of the focus lens barrel 101a, so that the lens body 102a is uniformly stressed, and it is conceivable that the focus lens barrel 101a moves more stably to improve the projection effect.

The slider 61a is fixed to the second lens 1022 by a locking member. Specifically, the second lens 1022 has a locking hole 1020 communicated with the sliding guide 1013, the sliding member 61a has a through hole corresponding to the locking hole 1020, and the locking member passes through the sliding member 61a and is locked in the locking hole 1020 of the second lens 1022, so as to fixedly connect the sliding member 61a and the second lens 1022. In other embodiments, the sliding member 61a can be fixed to the second lens 1022 by snapping, bonding, welding, etc., and the present application is not limited thereto.

In the present embodiment, the slider 61a includes a mounting portion 613 and a stopper portion 614 connected to the mounting portion 613. The through hole 602 penetrates the mounting portion 613 and the stopper portion 614. The stopping portion 614 is stopped by the slide guiding groove 1013. The mounting portion 613 is slidably received in the guide groove 1013 and is fixedly connected to the second lens 1022. The stopping portion 614 has a receiving groove 603 formed at an edge of the through hole 602 and communicating with the through hole 602, and the magnetic member is received in the receiving groove 603. The circuit board is fixed on the focusing lens barrel 101a, and the magnetic sensor arranged on the circuit board is arranged opposite to the magnetic member, so that the overall structure of the automatic focusing device 1a is simplified, and the automatic focusing device is suitable for miniaturization design.

It will be appreciated that in some embodiments, the stop 614 may be omitted, i.e., the slider 61a or the locking member is made of a magnetic material to function as a magnetic member. In other embodiments, a magnetic member is disposed on the mounting portion 613 of the slider 61 a.

In the present embodiment, the slide guide 1013 is a kidney-shaped groove extending along the optical axis. The dimension of the guide link 1013 is larger than the dimension of the mounting portion 613 in the slot length direction along the optical axis; in the groove width direction perpendicular to the optical axis, the size of the sliding guide groove 1013 is equal to the size of the mounting portion 613, so that when the focusing element rotates, the second lens 1022 is driven to move only in the optical axis direction, and cannot rotate in the circumferential direction perpendicular to the optical axis direction, so that the lens group cannot rotate when mounted on the second lens 1022, and the optical effect of the automatic focusing device 1a is ensured.

Referring to fig. 1 to 14, fig. 14 is a flowchart illustrating an auto-focusing method according to an embodiment of the present disclosure. As shown in fig. 14, the auto-focusing method, applied to the projection apparatus 1000 described above, includes the following steps.

Step S141, a defocus parameter of the lens body is acquired.

The defocus parameter can be obtained by analyzing image data corresponding to the current projection picture, where the image data includes, but is not limited to, the light spot. The defocus parameter can be obtained by combining the magnetic inductor with the software algorithm of the projection apparatus 1000 according to the control module 3 of the auto-focusing

apparatus

1, 1a, and optionally combining a camera, especially a Time of Flight (TOF) camera, to calculate the defocus parameter of the lens body 102. It should be noted that the defocus parameter obtaining method can be obtained by using an existing defocus parameter measuring method, and the application is not limited in particular.

And S142, when the defocusing parameters meet the preset conditions, detecting a first magnetic signal corresponding to the current position of the magnetic piece through the magnetic inductor.

It can be understood that the control module 3 may pre-establish a corresponding relationship between the position of the magnetic member 62 and the strength of the magnetic signal, so that when the magnetic signal is determined, the real-time position of the magnetic member 62 can be rapidly obtained according to the corresponding relationship, so as to rapidly realize the focusing of the automatic focusing

apparatus

1, 1 a. The magnetic member may be at least one of a magnet and a magnetic alloy element, and the magnetic sensor 63 includes, but is not limited to, one or more of a linear tunneling magneto-resistive sensor, a linear hall sensor, an anisotropic magneto-resistive sensor, and a giant magneto-resistive sensor. The magnetic sensor 63 can sense the magnetic signal intensity of the magnetic member 62 in real time, so that the control module 3 can acquire the real-time position of the magnetic member 62 according to the sensed magnetic signal intensity, thereby greatly shortening the focusing time.

Step S143, calculating a focusing parameter of the lens body with clear focusing according to the defocusing parameter and the first magnetic signal; the focusing parameters comprise target positions of the magnetic pieces when the lens body is clearly focused.

It is understood that the control module 3 may establish a correspondence relationship between the focusing position of the lens body 102 and the position of the magnetic member 62 in advance.

And step S144, controlling the driving mechanism to drive the focusing piece to rotate according to the focusing parameters so as to drive the lens body to rotate around the optical axis direction, move relative to the focusing lens barrel in the optical axis direction and drive the sliding piece to move in the optical axis direction.

When the control module 3 determines that the lens body 102 is out of focus, it sends a driving signal to the driving mechanism 300, so that the driving motor 51 drives the gear 52 to rotate, and the rotation of the gear 52 drives the focusing rack 21 and the transmission member 22 to slide in the spiral groove 1012, so that the lens body 102 rotates around the optical axis direction and moves relative to the focusing lens barrel 101 in the optical axis direction, and the sliding member 61 moves in the optical axis direction. Because the magnetic element 62 moves synchronously with the sliding element 61, the intensity of the magnetic signal of the magnetic element 62 sensed by the magnetic sensor 63 changes, and the circuit board 500 can obtain the real-time position of the magnetic element 62 according to the received magnetic signal of the magnetic element 62 sensed by the magnetic sensor 63; or, the circuit board 500 sends the acquired magnetic signal to the control module 3 of the projection apparatus 1000, and the control module 3 calculates and obtains the real-time position of the magnetic member 62 according to the received magnetic signal.

In some embodiments, according to the focusing parameters, the driving mechanism is controlled to drive the focusing element to rotate so as to drive the lens body to move relative to the focusing lens barrel in the optical axis direction while rotating around the optical axis direction, and to drive the sliding to move in the optical axis direction, and the method further includes:

according to the focusing parameters, the driving mechanism is controlled to drive the focusing piece to rotate so as to drive the first lens of the lens body to move relative to the focusing lens barrel in the optical axis direction while rotating around the optical axis direction, and drive the second lens to slide in the optical axis direction and limit the second lens of the lens body to move relative to the focusing lens barrel only in the optical axis direction.

It can be understood that since the second lens 1022 can only move in the optical axis direction relative to the focus adjustment barrel 101, the lens group installed in the second lens 1022 will not rotate relative to the second lens 1022, thereby ensuring that the autofocus apparatus 1a has good optical effect even after focusing.

And step S145, finishing focusing when the magnetic inductor detects a second magnetic signal corresponding to the target position of the magnetic piece.

After the focusing position of the lens body 102 is determined, the control module 3 determines the position of the magnetic member 62 to be moved according to the corresponding relationship between the focusing position of the lens body 102 and the position of the magnetic member 62, and then determines the second magnetic signal according to the corresponding relationship between the magnetic signal of the magnetic member 62 and the position of the magnetic member. Therefore, the automatic focusing method can form closed-loop control, further can greatly improve the automatic focusing accuracy, and shortens the focusing time.

The autofocus methods provided herein may be implemented in hardware, firmware, or as software or computer code that may be stored in a computer readable storage medium, such as a CD, ROM, RAM, floppy disk, hard disk, or magneto-optical disk, or as computer code that is originally stored on a remote recording medium or a non-transitory machine readable medium, downloaded over a network, and stored in a local recording medium, such that the methods described herein may be presented using a general purpose computer or special purpose processor, or as software stored on a recording medium in programmable or dedicated hardware, such as an ASIC or FPGA. As can be appreciated in the art, a computer, processor, microprocessor, controller or programmable hardware includes a memory component, e.g., RAM, ROM, flash memory, etc., which can store or receive software or computer code when the software or computer code is accessed and executed by the computer, processor or hardware implementing the processing methods described herein. In addition, when a general-purpose computer accesses code for implementing the processing shown herein, execution of the code transforms the general-purpose computer into a special-purpose computer for performing the processing shown herein.

The computer readable storage medium may be a solid state memory, a memory card, an optical disc, etc. The computer-readable storage medium stores program instructions for the computer to call to execute the auto-focusing method shown in fig. 14.

The automatic focusing device provided by the embodiment of the invention has at least one of the following beneficial effects:

1. through the induction design of magnetic part and magnetic inductor, reach the ability that acquires focusing piece rotational position information in real time, in addition feedback control module cooperation driving motor to improve the precision of auto focus greatly.

2. The rotary position signal obtained through electromagnetic real-time induction can replace the existing optical coupler induction technology, real-time focusing piece position information is provided, the actions of calibration and forward focusing of the motor through the starting point optical coupler in automatic focusing are omitted, and the automatic focusing time is greatly shortened.

3. The method converts the large-range rotary motion into the small-range linear motion by utilizing a motion decomposition mode, and greatly reduces the detection range of the magnetic sensor and the design difficulty of a scheme.

4. Compared with the existing design scheme of a plurality of annular magnets, the magnet size is reduced, the design cost is reduced, and the algorithm is simplified, so that the focusing of the automatic focusing device can be more accurately realized.

It will be appreciated by those skilled in the art that the above-described preferred embodiments may be freely combined, superimposed, without conflict.

The above embodiments of the present invention are described in detail, and the principle and the implementation of the present invention are explained by applying specific embodiments, and the above description of the embodiments is only used to help understanding the method of the present invention and the core idea thereof; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. An autofocus apparatus, comprising:

the focusing piece is connected with the lens body in a matched manner;

a magnetic member;

2. The autofocus apparatus of claim 1, wherein the drive mechanism includes a bracket fixedly disposed on the focus lens barrel, and the slider is slidably disposed between the bracket and the focus lens barrel.

3. The autofocus apparatus of claim 2, wherein the holder defines a guide slot, the slider being slidably received in the guide slot, the guide slot extending parallel to the optical axis.

4. The autofocus apparatus of claim 2, wherein a side of the slider facing away from the holder is provided with a plurality of guide bars arranged at intervals, and a direction of extension of the plurality of guide bars is parallel to the optical axis direction.

5. The automatic focusing device of claim 2, wherein the bracket is provided with a clearance hole at a position corresponding to the magnetic member, and the magnetic member moves in the clearance hole along with the sliding member; alternatively, the first and second electrodes may be,

6. The autofocus apparatus of claim 2, wherein the focus barrel has a helical groove; the focusing piece can slide along the spiral groove and drive the lens body to rotate around the optical axis direction and move relative to the focusing lens barrel in the optical axis direction, and the sliding piece is driven to move in the optical axis direction.

7. The autofocus apparatus of claim 6, wherein the drive mechanism further comprises a drive motor fixed to the frame and a gear provided at an output end of the drive motor; the focusing piece comprises a focusing rack meshed with the gear and a transmission piece in sliding fit with the spiral groove; one end of the transmission piece is fixed on the lens body, and the other end of the transmission piece penetrates through the sliding piece and is fixed on the focusing rack; the gear is used for driving the focusing rack and the transmission piece to rotate around the direction of the optical axis.

8. The autofocus apparatus of claim 7, wherein the slider defines a driving slot through which the driving member passes, the driving slot extending in a direction different from the spiral slot.

9. The autofocus apparatus of claim 8, wherein the driving groove has an elongated shape, and the transmission member abuts against the slider in the groove width direction to slide relative to the slider in the groove length direction.

10. The autofocus apparatus of claim 7, wherein the focus rack is movably disposed on the mount and/or the slide.

11. The autofocus apparatus of claim 10, wherein the focus rack includes an engaging portion engaging with the gear and two connecting portions disposed on opposite sides of the engaging portion in the direction of the optical axis, and the holder is provided with a stopper portion slidably engaged with the two connecting portions.

12. The autofocus apparatus of claim 11, wherein the stop portion and the bracket and/or the slider together enclose a stop space in which the focus rack is movable.

13. The autofocus apparatus of claim 12, wherein the limiting portion comprises a first limiting portion and a second limiting portion disposed opposite to each other, and a gap is formed between the first limiting portion and the second limiting portion for the engagement portion to pass through;

14. The autofocus apparatus of claim 1, wherein the lens body includes a first lens and a second lens, the first lens being fixedly disposed with respect to the second lens in the optical axis direction, the first lens being rotatably disposed with respect to the second lens in a circumferential direction perpendicular to the optical axis direction; the focusing piece is fixedly connected with the first lens, and the sliding piece is arranged on the focusing lens barrel in a sliding mode and is fixedly connected with the second lens.

15. The autofocus apparatus of claim 14, wherein rotation of the focus member causes the first lens to rotate about an optical axis while moving relative to the focus barrel in the optical axis, and causes the slider to move in the optical axis to limit movement of the second lens relative to the focus barrel only in the optical axis.

16. The autofocus apparatus of claim 14, wherein the focus barrel defines a slide guide groove slidably engaged with the slider, the slide guide groove extending in a direction parallel to the optical axis.

17. A projection device comprising an optical housing and the autofocus apparatus of any of claims 1-16 mounted to the optical housing.

18. An auto-focusing method, characterized in that the method is applied to a projection apparatus as claimed in claim 17; the method comprises the following steps:

acquiring a defocusing parameter of the lens body;