CN108227107A - Lens assembly and photographic device using same - Google Patents

Abstract

The invention provides a lens assembly and a photographic device using the lens assembly. The lens assembly includes a lens holder, a lens and a locking part. The lens holder includes a front cover and a side cover extending from an edge of the front cover. An opening is defined in the front cover. The lens is arranged on the lens holder so that the optical axis of the lens is aligned with the opening. The engaging portion protrudes outward from the side cover, and the projection of the engaging portion in a direction parallel to the optical axis is located above the lens.

Description

Lens component and photographic device using the lens component

technical field

The invention relates to a lens assembly and a photographic device using the lens assembly, in particular to a photographic device using the lens assembly with a smaller volume.

Background technique

With the advancement of science and technology, the continuous enhancement of camera technology and the decline in price, the photography function has become the basic function of portable electronic products, so various portable electronic products such as mobile phones, personal digital assistants (PDA), notebook computers, tablet computers etc. are generally equipped with a small-scale camera so that users can take images of daily life.

Generally speaking, a small-scale camera includes an image sensor and a lens assembly. The image sensor is, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor sensor (CMOS sensor).

The lens assembly includes a lens barrel and a lens base, wherein the threaded part is arranged on the lens barrel and the lens base. During the assembly process of the lens barrel and the lens base through the threaded part, the position of the lens barrel relative to the lens base can be adjusted through the rotation of the lens barrel, so that the image is projected onto the image plane of the image sensor. The above-mentioned threaded portion inevitably increases the volume of the lens assembly and reduces the portability, which does not conform to the development trend of light and thin electronic devices. Therefore, a lens module that overcomes the above-mentioned structural limitations of the prior art is required.

On the other hand, Japanese Patent Laid-Open No. 2012-256040 discloses a lens module, wherein the lens is connected to the lens holder through an adhesive. The structural strength of this type of combination is weak, and due to the lack of personnel assembly, the lens may also be tilted relative to the lens holder, which is not conducive to the improvement of image quality.

Contents of the invention

A main objective of the present invention is to provide a miniaturized lens assembly, which includes an engaging portion for combining with a corresponding groove on the lens mount. The above-mentioned engaging part is provided without affecting the predetermined optical function of the lens assembly, and has smaller volume and lighter weight than the traditional lens assembly without thread structure.

Another main purpose of the present invention is to provide a photographic device using the miniaturized lens assembly, which has smaller volume and lighter weight.

According to some embodiments of the present invention, the lens assembly includes a lens holder, a lens, and a locking portion. The lens holder includes a front cover and a side cover extending from the edge of the front cover. An opening is defined in the front cover. The lens is arranged on the lens holder so that the optical axis of the lens is aligned with the opening. The engaging portion protrudes outward from the side cover, and a projection of the engaging portion in a direction parallel to the optical axis is located on the lens.

In the above embodiment, the engaging portion is closer to the light incident surface of the lens assembly than the lens, and the engaging portion is adjacent to the front cover. Alternatively, the engaging portion is farther away from the light incident surface of the lens assembly than the lens.

In the above embodiment, the side cover includes a first annular portion, a connecting portion and a second annular portion. The connecting portion is connected to a side of the first annular portion close to the front cover. The second annular portion is connected to the first annular portion via the connecting portion. In a direction perpendicular to the optical axis, the width of the second ring portion is smaller than the width of the first ring portion. The engaging portion is disposed on the second ring portion and has a distance from the connecting portion.

Alternatively, the side cover includes a first annular portion, a connecting portion and a second annular portion. The connecting portion is connected to a side of the first annular portion away from the front cover. The second annular portion is connected to the first annular portion via the connecting portion, wherein in a direction perpendicular to the optical axis, the width of the second annular portion is smaller than that of the first annular portion. The engaging portion is disposed on the second ring portion and has a distance from the connecting portion.

In the above embodiment, the lens assembly includes a plurality of fastening parts, and the fastening parts are disposed on the side cover at intervals in the circumferential direction.

In the above embodiment, the projection of the engaging portion in the direction parallel to the optical axis is located on the optically effective surface of the lens.

Another object of the present invention is to provide a photographing device. The photographing device includes the lens assembly and an image sensing element of any one of the above embodiments. The image sensing element is arranged along the optical axis of the lens and is configured to receive light passing through the lens.

In the above embodiments, the photographing device further includes a mirror base, a driving coil and a driving magnet. The mirror base includes a body surrounding the side cover and a protruding structure formed on the inner wall of the body. The engaging portion leans against the protruding structure to fix the lens assembly on the mirror base. The driving coil is arranged on the body of the mirror base, and the driving magnet is arranged opposite to the driving coil.

The advantages and beneficial effects of the lens assembly provided by the present invention and the photographic device using the same lie in that: the engaging part of the present invention is provided without affecting the predetermined optical function of the lens assembly, and compared with the traditional lens assembly without thread structure Has smaller volume and lighter weight.

Description of drawings

Complete disclosure is made according to the following detailed description and in conjunction with the accompanying drawings. It should be noted that, in accordance with the usual practice in the industry, the drawings are not necessarily drawn to scale. In fact, the dimensions of the elements may be arbitrarily expanded or reduced for clarity of illustration.

FIG. 1 is an exploded view of the structure of a camera device according to some embodiments of the present invention.

Fig. 2 is a partial structural diagram of a mirror base according to some embodiments of the present invention.

3A is a perspective view of a lens assembly according to some embodiments of the present invention.

3B is a side view of a lens assembly according to some embodiments of the present invention.

FIG. 4 is a schematic cross-sectional view of a lens assembly according to some embodiments of the present invention.

5 is a schematic diagram of an assembly method of a lens assembly and a mirror base according to some embodiments of the present invention, wherein the engaging portion is not combined with the protruding structure.

6 is a schematic diagram of an assembly method of a lens assembly and a mirror base according to some embodiments of the present invention, wherein the engaging portion is combined with the protruding structure.

7A is a perspective view of a lens assembly according to some embodiments of the present invention.

7B is a side view of a lens assembly according to some embodiments of the present invention.

FIG. 8 is a schematic cross-sectional view of a lens assembly according to some embodiments of the present invention.

9A is a perspective view of a lens assembly according to some embodiments of the present invention.

9B is a side view of a lens assembly according to some embodiments of the present invention.

FIG. 10 is a schematic cross-sectional view of a lens assembly according to some embodiments of the present invention.

Explanation of reference signs:

1～Lens driver module

2～Electromagnetic drive components

3, 3a, 3b～lens assembly

5～circuit board

7～light sensing element

10～shell

101～Upper shell

102～side shell parts

12～base

14～circuit board

16～coil substrate

162～OIS drive coil

164～OIS drive coil

166 ~ depression

20～frame

201～side frame

202～Accommodating tank

22～upper shrapnel

24～Lower shrapnel

26～mirror holder

261～Body

2611～inner wall

2612～lower side edge

2613～upper edge

263～Protrusion structure

2631～Part 1

2632～Part II

265～channel

28～drive coil

29～Magnetic components

31, 31b～Lens holder

32～front cover

33, 33b～side cover

331～annular part (first annular part) (second annular part)

332～connection part

333～annular part (first annular part) (second annular part)

334～connection part

335～annular part (second annular part) (third annular part)

336～connection part

337～annular part (second annular part)

34～Lens unit

341, 342, 343, 344～Lens

36, 36a, 36b~Engaging part

40～Loop line

a～arrow

H1～Height

H2～Height

D1～Space

D2～Space

R1～extended line segment

O～optical axis

Detailed ways

Several specific preferred embodiments will be cited below and described in detail with the accompanying drawings, which show several embodiments. However, the present invention can be implemented in many different forms, and is not limited to the embodiments described below. The embodiments provided here can make the disclosure more thorough and complete, so as to fully convey the scope of the present invention to those skilled in the art .

It must be understood that elements not specifically described or shown in the drawings may exist in various forms well known to those skilled in the art. In addition, when a component is "on" another component or substrate, it may mean "directly" on another component or substrate, or that a certain component is on another component or substrate, or that a component is interposed between other components or substrates. other components.

In addition, relative terms such as "lower" or "bottom" and "higher" or "top" may be used in the embodiments to describe the relative relationship of one element to another element in the drawings. It will be understood that if the device of the figures is turned over so that it is upside down, elements described as being on the "lower" side would then become elements on the "higher" side.

Here, terms such as "about" and "approximately" usually mean within 20%, preferably within 10%, and more preferably within 5% of a given value or range. The quantities given here are approximate quantities, which means that the meanings of "about" and "approximately" can still be implied without specific instructions.

FIG. 1 shows an exploded view of the structure of a camera device 1 according to some embodiments of the present invention. The photographic device 1 includes an electromagnetic drive assembly 2 , a lens assembly 3 , a main circuit board 5 and an image sensing element 7 . The electromagnetic driving assembly 2 is configured to carry the lens assembly 3 and control the displacement of the lens assembly 3 . The image sensing element 7 is disposed on the main circuit board 5 and faces the last lens of the lens assembly 3 . The image sensing element 7 may include an image sensor composed of photosensitive elements such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS). When the photographing device 1 captures an image, the light travels along the optical axis O of the lens assembly 3 , and then enters the image sensing element 7 . The image sensing element 7 senses the light and sends out an electronic signal to generate an image.

According to some embodiments of the present invention, the structural features of the electromagnetic drive assembly 2 are described as follows.

1, in some embodiments, the electromagnetic drive assembly 2 includes a housing 10, a base 12, a circuit board 14, a coil substrate 16, a frame 20, an upper elastic piece 22, The lower shrapnel 24, a bearing seat 26, a focus driving coil 28, a plurality of magnetic elements (for example: four magnetic elements 29) and a plurality of lifting ring wires (for example: four lifting ring wires 40). The elements of the electromagnetic drive assembly 2 can be increased or decreased according to requirements, and are not limited to this embodiment.

The housing 10 includes an upper shell 101 and a side shell 102 . The upper shell 101 is rectangular, and the side shell 102 extends from the edge of the upper shell 101 toward the base 12 and is connected to the base 12 . The housing 10 and the base 12 define an inner space for accommodating other components of the electromagnetic driving assembly 2 .

The circuit board 14 is disposed on the base 12 and configured to electrically connect a control module (not shown) and the internal electronic components of the electromagnetic driving module 2 . The coil substrate 16 is disposed on the circuit board 14 and includes a plurality of OIS driving coils, such as two OIS (optical image stabilization; optical image stabilization) driving coils 162 and two OIS driving coils 164 .

The frame body 20 includes four side frame elements 201 connected in sequence around the optical axis O, and each side frame element 201 includes a receiving groove 202 formed thereon. The mirror base 26 is surrounded by the frame body 20 . The upper elastic piece 22 and the lower elastic piece 24 are respectively arranged on opposite sides of the frame body 20 and the mirror base 26 in the direction parallel to the optical axis O, so that the mirror base 26 can move relative to the frame body 20 along the vertical direction (Z direction). Each ring wire 40 is connected between the upper elastic piece 22 and the base 12 , so that the frame 20 can move relative to the base 12 in a direction perpendicular to the optical axis O. As shown in FIG.

The driving coil 28 is a ring structure surrounding the outer surface of the mirror base 26 , and configured for a current to pass through to generate a magnetic field to drive the mirror base 26 to move relative to the base 12 . The four magnetic elements 29 are respectively disposed on the four side frame members 201 . The positioning is carried out by the frame body 20 , the four magnetic elements 29 are arranged corresponding to the focusing driving coil 28 , and the four magnetic elements 29 are arranged corresponding to the OIS driving coils 162 and 164 .

FIG. 2 shows a partial structural schematic view of the mirror base 26 according to some embodiments of the present invention. In some embodiments, the mirror base 26 includes an annular body 261 and a plurality of protruding structures (for example, four protruding structures 263 , which are more clearly shown in FIG. 1 ). Four protruding structures 263 are arranged on the inner wall 2611 of the body 261, and each extends a predetermined length in the circumferential direction of the body 261, wherein the four protruding structures 263 are equidistantly spaced, and the four channels 265 are defined in two adjacent between the raised structures 263 .

In some embodiments, each protruding structure 263 includes a first portion 2631 and a second portion 2632 connected to the first portion 2631 . In the direction perpendicular to the optical axis O ( FIG. 1 ), the height of the first portion 2631 is greater than the height of the second portion 2633 . For example, the first portion 2631 has a height H1, the second portion 2633 has a height H2, and the height H1 is greater than the height H2.

Moreover, in the direction perpendicular to the optical axis O, the distance between the top surface of the first part 2631 and the upper edge 2613 of the body 261 is smaller than the distance between the top surface of the second part 2632 and the upper edge 2613 of the body 261 . For example, the first portion 2631 is aligned with the upper side edge 2613 of the body 261 , and the second portion 2632 is spaced apart from the upper side edge 2613 of the body 261 by a distance D1. In addition, the bottom surface of the first part 2631 is aligned with the bottom surface of the second part 2632 and spaced apart from the lower side edge 2612 of the main body 261 .

According to some embodiments of the present invention, the structural features of the lens assembly 3 are described as follows.

FIG. 3A shows a perspective view of the lens assembly 3 , and FIG. 3B shows a side view of the lens assembly 3 . In some embodiments, the lens assembly 3 includes a lens holder 31 , a lens unit 34 and a plurality of engaging portions (for example, four engaging portions 36 ). The lens holder 31 is used for accommodating the lens unit 34 and includes a front cover 32 and a side cover 33 . An opening 320 is defined in the center of the front cover 32 . The side cover 33 extends from the edge of the front cover 32 toward the direction away from the front cover 32 .

As shown in FIG. 3B , the side cover 33 includes a plurality of ring parts, such as ring parts 331 , 333 and 335 , and a plurality of connecting parts, such as connecting parts 332 and 334 . The annular portions 331 , 333 and 335 are respectively disposed around the optical axis O of the lens unit 34 and substantially extend along a direction parallel to the optical axis. For the convenience of description, in this embodiment, the annular portion 331 is referred to as a “first annular portion”, the annular portion 333 is referred to as a “second annular portion”, and the annular portion 335 is referred to as a “third annular portion”.

In a direction perpendicular to the optical axis O, the width of the first annular portion 331 is greater than that of the second annular portion 333 , and the width of the second annular portion 333 is greater than that of the third annular portion 331 . The connecting portion 332 is connected between the first annular portion 331 and the second annular portion 333 , and forms an angle greater than 0 with the first annular portion 331 and the second annular portion 333 , for example, 90 degrees. The connecting portion 334 is connected between the second annular portion 333 and the third annular portion 335 , and forms an included angle greater than 0 with the second annular portion 333 and the third annular portion 335 , for example, 45 degrees.

FIG. 4 shows a schematic cross-sectional view of the lens assembly 3 of some embodiments of the present invention. In some embodiments, the lens unit 34 is disposed in the lens holder 31 and includes a plurality of lenses, such as lenses 341 , 342 , 343 , 344 , which are sequentially arranged in a direction away from the front cover 32 . The optical axes of the lenses 341 , 342 , 343 , 344 pass through the openings 320 of the front cover 32 respectively, and the lenses that are farther away from the front cover 32 have larger widths along the vertical optical axis O direction.

Continuing to refer to FIG. 4 , together with reference to FIG. 2 , FIG. 3A and FIG. 3B , the four engaging portions 36 respectively extend from the side cover 33 in a direction perpendicular to the optical axis O, among which the four engaging portions 36 and the front cover 32 The distances are the same, and the four engaging portions 36 are arranged at equidistant intervals in the circumferential direction. In some embodiments, the four engaging portions 36 are disposed at positions where the second ring portion 333 is closer to the connecting portion 334 . In the embodiment shown in FIG. 3A and FIG. 3B , the four engaging portions 36 are disposed adjacent to the connecting portion 334 and separated from the connecting portion 332 by a distance D2 . The distance D2 may be greater than or equal to the height H2 of the second portion 2633 of the protrusion structure 263 ( FIG. 2 ).

In some embodiments, in the direction perpendicular to the optical axis O, the extension lengths of the four engaging portions 36 are equal to or smaller than the width difference between the first ring portion 331 and the second ring portion 333 . That is, the positions of the ends of the four engaging portions 36 do not exceed the extension line segment R1 of the first annular portion 331 in the direction parallel to the optical axis O, as shown in FIG. 4 .

In some embodiments, in the direction perpendicular to the optical axis O, the extension lengths of the four engaging portions 36 are equal to or smaller than the thickness of the protruding structure 2633 ( FIG. 2 ). In addition, in the direction parallel to the optical axis O, the heights of the four engaging portions 36 are equal to or smaller than the distance D1 between the second portion 2632 of the protruding structure 2633 ( FIG. 2 ) and the upper edge 2613 of the body 261 .

In some embodiments, at least a part of the projection of the four engaging portions 36 in the direction parallel to the optical axis O is located on at least one lens of the lens unit 34 . For example, in the embodiment shown in FIG. 4 , the projections of the four engaging portions 36 in the direction parallel to the optical axis O completely fall on the lens 344 , and the four engaging portions 36 are closer to the lens 344 Front cover 32. In some non-limiting embodiments, part of the projections of the four engaging portions 36 in the direction parallel to the optical axis O falls on the optically effective surface of the lens 344 (curved surface of the lens 344 ).

Referring to FIG. 5 and FIG. 6 , the steps of combining the lens assembly 3 with the mirror holder 26 are described as follows. Firstly, the engaging portion 36 of the lens assembly 3 is inserted into the channel 265 defined between adjacent protruding structures 263 until the connecting portion 332 of the lens assembly 3 abuts against the lower side edge 2612 of the protruding structure 263 . Next, rotate the lens assembly 3 in the direction indicated by the arrow a in FIG. The first part 2631 of the protruding structure 263 is shown in FIG. 6 .

In some embodiments, since the distance D2 ( FIG. 3B ) is equal to the height H2 ( FIG. 2 ) of the second portion 2633 of the protruding structure 2633 , the second portion 2632 of the protruding structure 263 is tightly fitted to the connecting portion 332 and snaps together. Between the parts 36 , the lens assembly 3 is firmly arranged on the mirror base 26 .

It should be understood that the present invention is not limited to the above-mentioned embodiments. In other embodiments, the distance D2 ( FIG. 3B ) is greater than the height H2 of the second portion 2633 of the raised structure 2633 ( FIG. 2 ). When the engaging portion 36 enters between the second portion 2632 of the protruding structure 263 and the upper side edge 2613 of the body 261 , a glue can be applied in the channel 265 to limit the movement of the lens assembly 3 relative to the lens holder 26 , Then the lens assembly 3 is fixed in position.

Referring to FIG. 4 , in the above embodiment, the lens assembly 3 is combined with the mirror holder 26 through the engaging portion 36 . Since the distance between the end of the engaging portion 36 and the optical axis O is less than half of the maximum width of the lens holder 31 perpendicular to the optical axis O. Therefore, the width of the lens assembly 3 is smaller than the width of the lens assembly formed with the threaded part in the prior art. On the other hand, since the engaging portion 36 is supported by the protruding structure 263 , the lens assembly 3 will not tilt relative to the mirror base 26 , thereby improving the image quality of the photographing device 1 .

It should be understood that the form of the lens assembly 3 of the present invention is not limited to the above-mentioned embodiments, and various exemplary embodiments of the lens assembly of the present invention are presented below.

FIG. 7A shows a perspective view of the lens assembly 3a, FIG. 7B shows a side view of the lens assembly 3a, and FIG. 8 shows a schematic cross-sectional view of the lens assembly 3a. In the embodiment shown in FIG. 7A , FIG. 7B and FIG. 8 , the same or similar features as in the embodiment shown in FIG. 3A , FIG. 3B and FIG. 4 will be given the same reference numerals, and the features will not be described again. , to simplify the description.

In this embodiment, the lens assembly 3 a includes a lens holder 31 , a lens unit 34 and a plurality of engaging portions (eg, four engaging portions 36 a ). For the convenience of description, in this embodiment, the annular portion 333 is referred to as a “first annular portion”, and the annular portion 335 is referred to as a “second annular portion”.

The four engaging portions 36a respectively extend from the side cover 33 in a direction perpendicular to the optical axis O, wherein the distances between the four engaging portions 36a and the front cover 32 are the same, and the four engaging portions 36a are arranged at equal intervals in the circumferential direction. In some embodiments, the four engaging portions 36 a are disposed at positions where the second annular portion 335 is closer to the front cover 32 . In the embodiment shown in FIGS. 7-8 , the four engaging portions 36 a are disposed adjacent to the front cover 32 and are separated from the connecting portion 334 by a distance.

In some embodiments, in the direction perpendicular to the optical axis O, the extension lengths of the four engaging portions 36 a are equal to or smaller than the width difference between the first ring portion 333 and the second ring portion 335 . That is, the positions of the ends of the four engaging portions 36a do not exceed the extension line segment R2 of the first annular portion 333 in the direction parallel to the optical axis O, as shown in FIG. 8 .

In some embodiments, at least a part of the projections of the four engaging portions 36 a in the direction parallel to the optical axis O is located on at least one lens of the lens unit 34 . For example, in the embodiment shown in FIG. 8, the projections of the four engaging portions 36a in the direction parallel to the optical axis O completely fall on the lens 344, and the four engaging portions 36a are closer to the lens 344. Front cover 32. Moreover, the projected portions of the four engaging portions 36 a in the direction parallel to the optical axis O fall on the lens 343 , wherein the four engaging portions 36 a are closer to the front cover 32 than the lens 343 . In some non-limiting embodiments, part of the projections of the four engaging portions 36 a in the direction parallel to the optical axis O completely falls on the optically effective surface of the lens 344 (curved surface of the lens 344 ).

FIG. 9A shows a perspective view of the lens assembly 3b, FIG. 9B shows a side view of the lens assembly 3b, and FIG. 10 shows a schematic cross-sectional view of the lens assembly 3b. In the embodiment shown in Fig. 9A, Fig. 9B, Fig. 10, the same or similar features as in the embodiment shown in Fig. 3A, Fig. 3B, Fig. 4 will be given the same reference numerals, and the features will not be described again, to simplify the description.

The lens assembly 3b includes a lens holder 31b, a lens unit 34 and a plurality of engaging portions (eg, four engaging portions 36b). Compared with the lens holder 31 , the lens holder 31 b further includes a connecting portion 336 and a ring portion 337 . The annular portion 337 is disposed around the optical axis O of the lens unit 34 and substantially extends along a direction parallel to the optical axis. The width of the ring portion 331 is larger than that of the ring portion 337 , and the ring portion 337 is connected to the side of the ring portion 331 away from the front cover 32 through the connecting portion 336 . The connecting portion 336 and the annular portion 331 and the annular portion 337 respectively define an included angle greater than 0, for example, 90 degrees. For the convenience of description, in this embodiment, the annular portion 331 is referred to as a “first annular portion”, and the annular portion 337 is referred to as a “second annular portion”.

The four engaging portions 36b respectively extend from the side cover 33b in a direction perpendicular to the optical axis O, wherein the distances between the four engaging portions 36b and the front cover 32 are the same, and the four engaging portions 36b are equidistantly spaced in the circumferential direction. Specifically, the four engaging portions 36 b are disposed at positions where the second annular portion 337 is farther away from the front cover 32 . In the embodiment shown in FIGS. 9-10 , the four engaging portions 36 b are disposed adjacent to an end of the side cover 33 b away from the front cover 32 , and are separated from the connecting portion 336 by a distance.

In some embodiments, in the direction perpendicular to the optical axis O, the extension lengths of the four engaging portions 36 b are equal to or smaller than the width difference between the first ring portion 331 and the second ring portion 337 . That is, the positions of the ends of the four engaging portions 36 b do not exceed the extension line segment R3 of the first annular portion 331 in the direction parallel to the optical axis O, as shown in FIG. 10 .

In some embodiments, at least a part of the projections of the four engaging portions 36 b in the direction parallel to the optical axis O is located on at least one lens of the lens unit 34 . For example, in the embodiment shown in FIG. 10 , the projected parts of the four engaging portions 36b in the direction parallel to the optical axis O fall on the lens 344, and the four engaging portions 36b are farther away from the lens 344. Front cover 32.

Although the present invention has been invented above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall prevail as defined by the appended claims.

Claims (10)

1. A lens assembly, characterized in that the lens assembly comprises: A lens holder, including a front cover and a side cover extending from the edge of the front cover, wherein an opening is defined in the front cover; a lens is arranged on the lens holder so that the optical axis of the lens is aligned with the opening; and An engaging portion protrudes outward from the side cover, wherein a projection of the engaging portion in a direction parallel to the optical axis is located on the lens. 2. The lens assembly according to claim 1, wherein the engaging portion is closer to the light incident surface of the lens assembly than the lens. 3. The lens assembly as claimed in claim 2, wherein the engaging portion is adjacent to the front cover. 4. The lens assembly according to claim 1, wherein the engaging portion is farther away from the light incident surface of the lens assembly than the lens. 5. The lens assembly according to any one of claims 1-4, wherein the side cover comprises: a first annular portion; a connecting portion, connecting one side of the first annular portion close to the front cover; and a second annular portion, connected to the first annular portion via the connecting portion, wherein in a direction perpendicular to the optical axis, the width of the second annular portion is smaller than the width of the first annular portion; Wherein the engaging portion is disposed on the second annular portion and is separated from the connecting portion by a distance. 6. The lens assembly according to any one of claims 1-4, wherein the side cover comprises: a first annular portion; a connecting part, connecting the side of the first annular part away from the front cover; and a second annular portion, connected to the first annular portion via the connecting portion, wherein in a direction perpendicular to the optical axis, the width of the second annular portion is smaller than the width of the first annular portion; Wherein the engaging portion is disposed on the second annular portion and is separated from the connecting portion by a distance. 7. The lens assembly according to any one of claims 1-4, characterized in that it comprises a plurality of fastening parts, and the fastening parts are disposed on the side cover at intervals in a circumferential direction. 8. The lens assembly according to any one of claims 1-4, wherein a projection of the engaging portion in a direction parallel to the optical axis is located on the optically effective surface of the lens. 9. A photographic device, characterized in that the photographic device comprises: A lens holder, including a front cover and a side cover extending from the edge of the front cover, wherein an opening is defined in the front cover; A lens is arranged on the lens holder so that the optical axis of the lens is aligned with the opening; an engaging portion protruding outward from the side cover, wherein the projection of the engaging portion in a direction parallel to the optical axis is located on the lens; and An image sensing element is arranged along the optical axis of the lens and configured for receiving light passing through the lens. 10. The photographing device according to claim 9, wherein the photographing device further comprises: A mirror base, including a main body arranged around the side cover and a raised structure formed on the inner wall of the main body, wherein the engaging portion abuts against the raised structure to fix the lens assembly on the mirror base ; a driving coil disposed on the body of the mirror base; and A driving magnet is arranged opposite to the driving coil.