Camera actuator and light refraction camera module comprising it

Abstract

Disclosed is a camera actuator for implementing an auto focus and zoom function, and an optical refraction camera module including the same. The camera actuator of the present invention includes a housing, a driving portion installed to the housing and configured of a vibration shaft extending in a first direction and a vibration generator applying vibration to the vibration shaft in the first direction, a movable portion provided in correspondence to the driving portion and moving in the first direction within the housing by a driving force generated by the driving portion, a frictional moving portion moving in the first direction on the vibration shaft, and a connecting portion connecting the frictional moving portion and the movable portion corresponding to each other, the connecting portion being configured of a protrusion or a groove formed in a side surface portion of the frictional moving portion opposite to the movable portion, and a groove or a protrusion formed in a side surface portion of the movable portion in a manner to engage with the protrusion or the groove.

Description

Technical Field

[0001] This invention relates to camera actuators, and more particularly to camera actuators suitable for use in a folded zoom camera module for achieving high-magnification zoom and autofocusing, and a folded zoom camera module including the same. Background Technology

[0002] Previously, camera modules mounted on mobile devices mostly achieved zoom and autofocus by moving an optical system consisting of multiple lenses in the direction of the incoming light, i.e., the optical axis. In this case, the direction of movement of the optical system corresponds to the thickness direction of the mobile device when the camera module is mounted. Therefore, it was previously necessary to ensure a minimum amount of space for the optical system of the camera module to move along the thickness direction of the mobile device.

[0003] In other words, in the case of most previous camera modules, the optical system moved in the thickness direction of the mobile device. When installed in the mobile device, it was necessary to ensure the minimum space required for its installation in the thickness direction of the mobile device. Therefore, in the context of the recent trend of minimizing the thickness of mobile devices, its structure could not meet the market demand.

[0004] In the past, attempts were made to reduce the size of the optical system itself by adjusting the angle, size, spacing, and focal length of the lenses. However, this method physically reduces the size of the zoom lens and even the zoom lens barrel, thus limiting the ability to achieve thinner designs and potentially compromising the essential characteristics of the zoom lens.

[0005] To address this, a Folded zoom camera module was developed: a reflective system is installed to reflect light flowing in from the outside at a 90-degree angle, and an optical system through which the light refracted in the reflective system passes is placed horizontally in the width or length direction of the mobile device. This ensures sufficient spacing between the lenses constituting the optical system, thereby achieving high-magnification optical zoom and a thinner profile.

[0006] Unlike existing methods that vertically stack sensors (CCD, CMOS, etc.) and lenses, the light-refracting camera module uses a periscope structure, achieving high-magnification optical zoom without increasing the overall height. Furthermore, unlike existing methods that vertically stack lenses, the periscope structure significantly facilitates module thinning compared to conventional methods.

[0007] As a core element that decisively influences the zoom performance of a camera, this includes not only the specifications of the lenses that constitute the optical system, but also the driving range of the optical system. The larger the driving range of the optical system, the higher the zoom performance can be achieved. In the past, small cameras equipped with zoom lenses mainly used stepping motors as the driving mechanism to increase the driving range of the optical system.

[0008] However, the traditional stepping motor method suffers from the problem of increased overall size of the small camera due to the size of the stepping motor itself. In other words, because the stepping motor is relatively large, sufficient space is required to install it, which necessitates increasing the overall size of the small camera.

[0009] Thus, the stepper motor method, which is used as the optical system drive device in conventional light refraction camera modules, has the disadvantage of hindering the miniaturization of the device. To address this, as a countermeasure to the conventional stepper motor method, the piezoelectric method, utilizing piezoelectric elements, has received considerable attention in recent years. The piezoelectric method is based on the principle of using the vibrations that occur when a high-frequency pulse voltage is applied to a piezoelectric element to drive the optical system.

[0010] This piezoelectric method uses significantly smaller piezoelectric elements compared to existing stepper motors, thus offering the advantage of miniaturization for camera modules. Furthermore, the piezoelectric elements that generate the driving force are considerably lighter than existing stepper motors, further reducing the overall weight of the camera module. In other words, it also enables product weight reduction.

[0011] Figure 10 This is a schematic diagram of a piezoelectric optical system drive device suitable for camera modules.

[0012] Reference Figure 10 The conventional piezoelectric optical system drive device 8 includes a piezoelectric element 80 and a vibration shaft 82 fixed to one side thereof. A friction member 70 is integrally formed on the side of the lens barrel 7 constituting the optical system. The friction member 70 is coupled in a structure that surrounds a portion of the outer surface of the vibration shaft 82 in the circumferential direction, thereby being fixed to the vibration shaft 82 by frictional force between it and the vibration shaft 82, and moving along the vibration shaft 82 when the vibration shaft 82 vibrates.

[0013] In conventional piezoelectric optical system drive devices 8, when the piezoelectric element 80 vibrates rapidly in a first direction due to a high-frequency pulse voltage applied from the outside, the vibration shaft 82 also vibrates rapidly and repeatedly by elongating and contracting in the first direction (the axial direction of the vibration shaft). At this time, if the vibration shaft 82 moves rapidly in the elongation direction and slowly in the contraction direction, the friction member 70 and the lens barrel 7 move in the contraction direction of the vibration shaft 82.

[0014] Because when the vibration shaft 82 extends rapidly, the friction component 70 and the lens barrel 7 do not move due to the property of the lens barrel 7 to continue to remain stationary (stationary inertia). However, in the contraction direction of the relatively slow-moving vibration shaft, the friction component 70 and the lens barrel 7 move together in the contraction direction of the vibration shaft 82 by the frictional force acting between the friction component 70 and the vibration shaft 82.

[0015] In this structure, the drive device 8, consisting of the piezoelectric element 80 and the vibration shaft 82, only performs the function of simply moving the lens barrel 7 in the first direction. Therefore, more than one guide pin 9 is required for optical axis alignment of the lens barrel relative to the rear image sensor (not shown). At this time, the guide pin 9 also serves to guide the linear movement of the lens barrel in the first direction and suppress tilting while performing optical axis alignment.

[0016] However, the application of the guide pin 9 results in a complex structure, making assembly difficult and leading to decreased productivity. In particular, strict tolerance management is required during product manufacturing. Even a slight deviation in the parallelism between the guide pin 9 and the vibration shaft 82, or a bend in the vibration shaft 82, will prevent the lens barrel 7 from moving smoothly or render it immobile.

[0017] In particular, conventional piezoelectric optical system driving devices have been mainly used in conventional camera actuators to move the optical system in the thickness direction of mobile devices, but there are almost no cases of their application in light refraction camera modules. Therefore, it is necessary to develop a piezoelectric driving device that is suitable for the characteristics of light refraction camera modules.

[0018] [Existing Technical Documents]

[0019] [Patent Literature]

[0020] (Patent Document 1) Korean Patent Publication No. 2008-0085571 (Publication Date: September 24, 2008) Summary of the Invention

[0021] Technical issues

[0022] The technical problem to be solved by the present invention is to provide a camera actuator and a light refraction camera module including the camera actuator as follows: the piezoelectric method is advantageous for miniaturization and weight reduction compared with the conventional stepper motor method, and even if the optical axis of the vibration axis is slightly deviated or the vibration axis is bent during vibration, it will not affect the mobility of the optical system.

[0023] Methods for solving technical problems

[0024] As a means of solving the technical problem, one aspect of the present invention provides a camera actuator, which includes:

[0025] shell;

[0026] Two or more movable parts are mounted on the aforementioned housing and are driven independently of each other along a first direction to achieve zooming and autofocus; and

[0027] Two or more drive units are mounted on the aforementioned housing and are equipped with piezoelectric elements for driving each of the aforementioned movable units in a first direction.

[0028] The piezoelectric elements are arranged diagonally opposite each other with respect to an axis passing through the center of the movable part in a first direction.

[0029] It includes a ball guide that supports the movable part so that the movable part can roll in the first direction.

[0030] In addition, the aforementioned camera actuator also includes:

[0031] A frictional moving part that moves along a vibration axis connected to the piezoelectric element in a first direction; and

[0032] A connecting part that connects the aforementioned friction-moving part and the aforementioned movable part to each other.

[0033] The connecting portion is composed of a protrusion or groove formed on the side surface of the friction moving portion opposite to the movable portion, and a groove or protrusion formed on the side surface of the movable portion in a manner that engages with the protrusion or groove.

[0034] A preferred aspect of the camera actuator of the present invention includes:

[0035] shell;

[0036] The drive unit is mounted on the aforementioned housing and consists of a vibration shaft extending in a first direction and a vibration generator that applies vibration to the aforementioned vibration shaft in the first direction.

[0037] A movable part is provided corresponding to each of the aforementioned drive parts, and moves within the housing in a first direction by the driving force generated by the aforementioned drive parts;

[0038] The friction moving part moves in a first direction on the aforementioned vibration shaft; and

[0039] The connecting part connects the aforementioned friction-moving part and the movable part to each other.

[0040] The connecting portion is composed of a protrusion or groove formed on the side surface of the friction moving portion opposite to the movable portion, and a groove or protrusion formed on the side surface of the movable portion in a manner that engages with the protrusion or groove.

[0041] Preferably, the protrusion is a magnet, and a thin plate of magnetic material is attached to one side of the groove to generate attraction between the protrusion and the magnet, so as to suppress the movement of the protrusion in the first direction within the grooved area and allow the protrusion to move in a second direction orthogonal to the first direction.

[0042] As another preferred example, the protrusion is made of a magnetic material, and a thin plate magnet is attached to one side of the groove. The thin plate magnet and the protrusion of the magnetic material generate an attraction so as to suppress the movement of the protrusion in a first direction within the grooved area and allow the protrusion to move in a second direction orthogonal to the first direction.

[0043] As another preferred example, an elastic unit is provided on one side of the groove, which is elastically attached to the protrusion, so as to suppress the movement of the protrusion in the first direction within the grooved area and allow the protrusion to move in a second direction orthogonal to the first direction.

[0044] In this case, the aforementioned elastic unit is a leaf spring that applies elastic force to the protrusion by being in close contact with the other side of the groove opposite to one side of the protrusion, or a positioning ball plug consisting of a ball and a spring.

[0045] Furthermore, the drive unit applicable to the present invention is configured in two or more forms, and the movable part is configured in two or more forms, so as to correspond one-to-one with the two or more drive units.

[0046] Preferably, the driving unit is composed of a first driving unit and a second driving unit. The first driving unit is mounted adjacent to the first sidewall of the housing and is composed of a vibration shaft extending in a first direction and a vibration generator that applies vibration to the vibration shaft in the first direction. The second driving unit is mounted adjacent to the second sidewall opposite to the first sidewall of the housing and has the same structure as the first driving unit but with the vibration generator in the opposite position. The movable part is composed of a first movable part and a second movable part. The first movable part moves in translation in the first direction within the housing by the driving force generated by the first driving unit. The second movable part is arranged in series with the first movable part in the first direction within the housing and moves in translation in the first direction within the housing by the driving force generated by the second driving unit.

[0047] At this time, two or more movable parts are driven independently in the first direction by their respective driving parts.

[0048] In addition, at least two Hall sensors are spaced apart and aligned in a first direction on each of the first sidewall and the second sidewall that are opposite to each other in the housing. Hall magnets are mounted on the side of the first movable part opposite to the first sidewall and the side of the second movable part opposite to the second sidewall, corresponding to the Hall sensors.

[0049] In addition, the movable part includes: a carrier; and a lens barrel, which is mounted on the carrier and houses a lens group consisting of multiple lenses.

[0050] In addition, the vibration generator of the aforementioned drive unit is a piezo motor that includes a piezoelectric element.

[0051] In addition, the aforementioned friction moving part is composed of a lower friction block and an upper friction clamp. The lower friction block has a groove with a cross-section formed in the shape of an arc or an angle. The upper friction clamp is connected to the upper part of the lower friction block with the vibration shaft in between. The cross-sectional shape is the same as the shape of the groove and is symmetrical with the groove vertically.

[0052] The camera actuator of one aspect of the present invention further includes a ball guide that guides translational movement of the movable part relative to the housing in a first direction between the housing and the movable part.

[0053] In this case, the ball guide is preferably composed of the following components: a pair of ball guides that extend along a first direction on the bottom upper surface of the housing and have a first ball groove continuously formed thereon in the first direction; a second ball groove that is formed on one side of the lower surface of the movable part and on the other side as an opposing part, corresponding to the first ball groove; and a ball that is sandwiched between the first ball groove and the second ball groove that are opposite to each other.

[0054] Preferably, the second ball groove is formed in a bag shape on one side of the lower surface of the movable part and on the other side as the opposite part, with an independent spatial form, at least two of them.

[0055] Each of the second ball grooves, which are formed in an independent spatial form, holds a ball.

[0056] In addition, in a camera actuator of one aspect of the present invention, the housing is made of a magnetic material, and a magnet is mounted on the lower surface of the movable part opposite to the upper surface of the bottom of the housing.

[0057] As a means of solving the problem, another aspect of the present invention provides a light refraction camera module, which includes:

[0058] One aspect of the camera actuator mentioned above;

[0059] A reflection system, positioned in front of the camera actuator with reference to the direction of light travel, reflects externally incident light toward the camera actuator; and

[0060] An image sensor unit is positioned behind the camera actuator with the direction of light propagation as a reference. It receives light passing through the camera actuator and generates and outputs corresponding image information based on the received light.

[0061] Invention Effects

[0062] According to an embodiment of the present invention, even if the alignment of the vibration shaft (or movable part) in the first direction deviates to some extent during the assembly process, or if the vibration shaft bends during vibration, causing a change in the gap between the movable part and the friction moving part, the connection part can cope with the change in the gap. Therefore, the movable part is completely unaffected and can move smoothly in the first direction.

[0063] That is, it can accurately and clearly solve the problem of the previous technology that affects the mobility of the movable part (the problem that the movable part cannot move smoothly or becomes immobile in the first direction) caused by the misalignment or bending of the vibration shaft (or movable part) or the unevenness of the gap between the movable part and the vibration shaft (the gap between the two needs to be kept uniform throughout the entire range of movement (Stroke) of the movable part).

[0064] Furthermore, the piezoelectric method, which is more compact and lightweight than conventional stepper motors, has a simple structure and is easy to assemble, thus offering advantages in mass production. Moreover, by using a magnet mounted on the lower surface of the movable part, the movable part can move smoothly and stably in a straight line through a ball guide when it is pressed tightly against the bottom side of the housing, eliminating the need for a separate guide pin for optical axis alignment. Attached Figure Description

[0065] Figure 1 This is an exploded perspective view of a camera actuator according to one aspect of the present invention.

[0066] Figure 2 This is a perspective view of a camera actuator according to one aspect of the present invention.

[0067] Figure 3 Viewed from above Figure 2 The image shows a top view of the camera actuator.

[0068] Figure 4 It is a three-dimensional view of the drive unit that incorporates frictional moving parts.

[0069] Figure 5 This is a diagram showing a preferred embodiment of the part (connecting part) that connects the friction moving part and the movable part.

[0070] Figure 6 This is a diagram showing several other preferred embodiments of the portion (connecting portion) that connects the friction moving part and the movable part.

[0071] Figure 7 The above is observed along the direction of line AA. Figure 3 The image shows a cross-sectional view of the camera actuator.

[0072] Figure 8 This is a three-dimensional view of the carrier that constitutes the movable part, viewed from the bottom.

[0073] Figure 9 This is a schematic diagram of a light-refracting camera module, which is another aspect of the present invention.

[0074] Figure 10This is a schematic diagram of a conventional piezoelectric optical system drive device. Detailed Implementation

[0075] The preferred embodiments of the present invention will now be described in detail.

[0076] The terminology used in this specification is for illustrative purposes only and is not intended to limit the scope of the invention. Unless otherwise specified, the singular form includes multiple meanings.

[0077] The terms "including" or "possessing" in this specification indicate the presence of the features, figures, steps, actions, constituent elements, components, or combinations thereof described in the specification, and do not preclude the possibility of the presence or addition of one or more other features or figures, steps, actions, constituent elements, components, or combinations thereof.

[0078] Furthermore, terms such as "first" and "second" are used to describe each constituent element, and the constituent elements mentioned above are not limited to these terms. These terms are only used to distinguish one constituent element from other constituent elements.

[0079] Furthermore, the terms "...part", "...unit", "...module" and other similar terms used in the instruction manual refer to units that process at least one function or action, which can be implemented by hardware or software or a combination of hardware and software.

[0080] When describing the invention with reference to the accompanying drawings, the same reference numerals are used for the same constituent elements, and repeated descriptions of these elements are omitted. Furthermore, when describing the invention, detailed descriptions of related prior art are omitted if it is determined that a detailed explanation of such art would obscure the essence of the invention.

[0081] In the following description of the invention, a three-axis coordinate system will be used for ease of explanation.

[0082] For reference, in a 3-axis coordinate system, the X-axis refers to the direction in which light (ray) passes through the actuator of the present invention, i.e., the optical axis direction. The term 'first direction' will be used below to describe directions that are aligned with or parallel to the X-axis. Furthermore, the Z-axis refers to the direction perpendicular to the X-axis, and the Y-axis refers to the direction orthogonal to the X-axis on a plane perpendicular to the Z-axis. The term 'second direction' will be used below to describe directions that are aligned with or parallel to the Y-axis.

[0083] According to one aspect of the present invention, a camera actuator is provided that uses vibration generated by a piezoelectric element to move a movable part including a lens barrel (optical system) any distance in the optical axis direction by means of an externally applied high-frequency pulse voltage, thereby providing a piezoelectric camera actuator that realizes zoom in and zoom out, and autofocusing.

[0084] In the following description of the present invention, an example will be illustrated and explained using a structure in which two movable parts are separately arranged along a first direction in a camera actuator, and a driving part is arranged corresponding to each of the two movable parts. Of course, this is only a preferred embodiment for illustrating the present invention, and the number of movable parts and driving parts is not limited to the illustrated configuration.

[0085] In other words, as a preferred embodiment for illustrating the present invention, the following description uses a structure with two movable parts and a driving part arranged in a single camera actuator as an example, but the movable parts and driving parts are not limited to two pairs. The number of movable parts and driving parts can be arbitrarily changed depending on the required specifications of the camera.

[0086] Figure 1 This is an exploded perspective view of a camera actuator according to one aspect of the present invention. Figure 2 This is a perspective view of a camera actuator according to one aspect of the present invention. Furthermore, Figure 3 Viewed from above Figure 2 The image shows a top view of the camera actuator.

[0087] Reference Figures 1 to 3 In one aspect, the camera actuator 3 of the present invention includes a housing 30. (See attached figures) Figure 1 and Figure 2 As shown in the figure, the outer shell 30 has a storage space (notation omitted) on the inner side. With the direction of light movement (first direction) as a reference, one side and the other side as the opposite part are open. The two side walls 302 and 304 in the second direction have openings 303 and 305 in the form of elongated slits in the first direction, respectively.

[0088] A ball guide rail 380, which will be described later, is formed on the upper surface of the inner bottom of the housing 30. In addition, at least one support member 309 with an arc-shaped groove (notation omitted) is formed on the upper surface of the bottom adjacent to the two side walls (hereafter, one side wall is referred to as 'first side wall 302' and the other side wall, which is the opposite part, is referred to as 'second side wall 304'). The vibration shaft 320, which will be described later, is placed on the support member 309.

[0089] An upper cover (not shown) is attached to the upper side of the aforementioned housing 30. Inside the housing 30 is a drive unit 32 and a movable part 34 that moves within the housing 30 along a first direction by the driving force generated by the drive unit 32. The drive unit 32 includes a vibration shaft 320 extending in the first direction. Additionally, a vibration generator 322 is provided that applies vibration to the vibration shaft 320 in the first direction.

[0090] The vibration shaft 320 of the drive unit 32 is disposed inside the housing 30 in the first direction and is supported in a floating state from the bottom of the housing 30 by the aforementioned support member 309. The vibration shaft 320 is preferably a ring-shaped rod with a circular cross-section, but it can also be a rod-shaped structure with an angular cross-section. Depending on the cross-sectional shape of the vibration shaft 320, the groove shape of the support member 309 also varies, and is therefore not limited to the illustrated arc shape.

[0091] A portion of the outer surface of the aforementioned vibration shaft 320 is mounted circumferentially in contact with the groove of the support member 309. When the vibration shaft 320 vibrates, to prevent it from detaching from the support member 309, an adhesive binds the two together (the vibration shaft 320 and the support member 309). Here, a soft epoxy adhesive can be used as the adhesive, possessing elasticity sufficient to allow piezoelectric action of the vibration shaft 320, which extends and contracts in the first direction via the vibration generator 322.

[0092] As shown in the figure, when there are two movable parts 34, there can also be two driving parts 32. For ease of explanation, the movable part located in front of the other movable part 34 relative to the direction of light movement will be referred to as 'first movable part 34a', and the movable part located behind the other movable part will be referred to as 'second movable part 34b'. Furthermore, the driving parts corresponding to the first movable part 34a and the second movable part 34b will be described as 'first driving part 32a' and 'second driving part 32b', respectively.

[0093] The first drive unit 32a is disposed adjacent to the first sidewall 302 of the housing 30 inside the housing 30. The first drive unit 32a consists of a vibration shaft 320 extending in a first direction and a vibration generator 322 that applies vibration to the vibration shaft 320 in the first direction. The second drive unit 32b is disposed adjacent to the second sidewall 304 inside the housing 30, and has the same structure as the first drive unit 32a, but with the vibration generator 322 positioned in the opposite direction.

[0094] That is, such as Figure 3As shown in the top view, the vibration generators 322 of the first drive unit 32a and the second drive unit 32b are arranged diagonally opposite each other with reference to an axis passing through the center of the two movable parts (34a, 34b). In this way, when the vibration generators 322 of the first drive unit 32a and the second drive unit 32b are arranged diagonally opposite each other, the relative spacing between the first drive unit 32a and the second drive unit 32b can be maximized within a limited space.

[0095] The vibration generators 322 of the first drive unit 32a and the second drive unit 32b are piezo motors that include a piezoelectric element that vibrates rapidly in a first direction by a high-frequency pulse voltage applied from the outside. One piezo motor is provided at one corner of one side of the housing 30 and another corner of the housing 30 in the diagonal direction. Furthermore, the two vibration axes 320 are parallel to each other and, when viewed in the second direction, have a structure that overlaps at least partially.

[0096] The first movable part 34a moves in a first direction along the ball guide rail 380 within the housing 30 by the driving force generated by the first drive part 32a. The second movable part 34b is disposed within the housing 30 at a predetermined distance from the first movable part 34a in the first direction, and moves in a first direction along the ball guide rail 380 within the housing 30 by the driving force generated by the second drive part 32b.

[0097] The first drive unit 32a and the first movable unit 34a, as well as the second drive unit 32b and the second movable unit 34b, are interconnected via the friction moving part 36 and the connecting part 37, described later. The first drive unit 32a and the second drive unit 32b are driven independently by individual signals output by a control unit, for example, a driver IC (not shown). Thus, the first movable unit 34a and the second movable unit 34b are also driven independently in a first direction via their respective drive units 32.

[0098] The first movable part 34a and the second movable part 34b each include a carrier 340. Additionally, a lens barrel 342 is provided for housing a lens group consisting of multiple lenses. The lens barrel 342 is mounted on the carrier 340 and moves together with it; however, depending on the situation, the carrier 340 may also be integrally formed on the lens barrel 342. In this case, each of the lenses constituting the lens barrel 342 has the same or different optical characteristics such as focal length and refractive index.

[0099] The aforementioned friction moving part 36 is configured to move along the respective vibration shaft 320 of the first drive part 32 and the second drive part 32b in a first direction. Furthermore, the friction moving part 36 is connected to the corresponding movable part 34 via a connecting part 37. Thus, when the vibration shaft 320 vibrates, the friction moving part 36 moves along the corresponding vibration shaft 320, resulting in the movable part 34, connected to the friction moving part 36 via the connecting part 37, moving in the first direction.

[0100] For example, when the vibration generator 322 of the first drive unit 32a vibrates rapidly in the first direction by a high-frequency pulse voltage applied from the outside, the corresponding vibration shaft 320 also vibrates rapidly and repeatedly by elongating and contracting in the first direction (the axial direction of the vibration shaft 320). At this time, when the vibration shaft 320 moves rapidly in the elongation direction and slowly in the contraction direction, the friction moving part 36 and the first movable part 34a move in the contraction direction of the vibration shaft 320.

[0101] This is because when the vibration shaft 320 extends rapidly, the friction moving part 36 and the first movable part 34a do not move because they need to maintain their stationary state (stationary inertia). However, in the contraction direction of the relatively slow-moving vibration shaft 320, the friction moving part 36 and the first movable part 34a connected thereto move together with the vibration shaft 320 in the contraction direction of the vibration shaft 320 due to the frictional force acting between the friction moving part 36 and the vibration shaft 320.

[0102] Figure 4 This is a diagram showing the drive unit that is combined with the friction moving part.

[0103] Reference Figure 4 As described above, the vibration shaft 320 of the drive unit 32 can be a ring-shaped rod with a circular cross-section, but is not limited to this. The friction moving part 36 is composed of a lower friction block 360 having a groove 362 with an arc or angular cross-section and an upper friction clamp 364 that is connected to the upper part of the lower friction block 360 with the same cross-section as the groove 362 and is symmetrical with the groove 362.

[0104] Regarding the shapes of the groove 362 and the upper friction clamp 364, they can be of any shape, as long as they are cross-sectional shapes that provide a friction surface in contact with a portion of the outer surface of the vibration shaft 320. For example, Figure 4 As shown, the groove and the upper friction clamp 364 are formed in a quadrilateral shape to create a total of four friction surfaces. At this time, the vibration shaft 320 can be in contact with all four friction surfaces, or with three surfaces, two surfaces, or even only one surface.

[0105] Figure 5This is a diagram showing a preferred embodiment of the part (connecting part) that connects the friction moving part and the movable part.

[0106] like Figure 5 As shown, the corresponding friction moving part 36 and movable part 34 are connected to each other by a connecting part 37. The connecting part 37 is composed of a protrusion 370 formed on the side surface of the friction moving part 36 opposite to the movable part 34 and a groove 372 formed on the side surface of the movable part 34 in a manner that engages with the protrusion 370. Alternatively, although not shown, it may be composed of a groove formed on the friction moving part 36 and a protrusion formed on the movable part 34.

[0107] The protrusion 370 constituting the connecting portion 37 is preferably a magnet, and a thin plate 371 of a magnetic material is attached to one side of the groove 372 (the side parallel to the second direction). In this case, the protrusion 370 is a magnet and the thin plate 371 is a magnetic material, thus generating an attraction between the two. Therefore, when the protrusion 370 is inserted into the groove 372, movement of the protrusion 370 in the first direction is suppressed, while movement in the second direction orthogonal to the first direction is allowed.

[0108] Therefore, even if the alignment of the vibration shaft 320 (or movable part) in the first direction deviates to some extent during the assembly process, or if the vibration shaft 320 bends during the vibration process caused by the vibration generator 322, resulting in a change in the gap between the movable part 34 and the friction moving part 36, the connecting part 37 can move in the second direction to cope with the change in the gap, so that the movable part 34 is completely unaffected and can move smoothly in the first direction.

[0109] That is, it can accurately and clearly eliminate the problem of the prior art that affects the mobility of the movable part 34 due to uneven spacing between the movable part 34 and the vibration shaft 320 caused by misalignment of the vibration shaft 320 (or bending of the vibration shaft 320) (the situation where the spacing between the two needs to be kept uniform within the overall movement range (Stroke) of the movable part but cannot be kept uniform) (the problem that the movable part cannot move smoothly in the direction of the optical axis or becomes immobile).

[0110] Depending on the circumstances, in contrast to the embodiments described above, the following variation may also exist: the protrusion 370 is made of a magnetic material, and a thin plate magnet (not shown) is attached to one side of the groove 372 (the side parallel to the second direction). The thin plate magnet generates an attraction between the protrusion 370 and the magnetic material, so as to suppress the movement of the protrusion 370 in the first direction within the area forming the groove 372 and allow the protrusion 370 to move in the second direction orthogonal to the first direction.

[0111] Figure 6 This is a diagram showing several other preferred embodiments of the portion (connecting portion) that connects the friction moving part and the movable part.

[0112] like Figure 6 As shown, as another preferred example, an elastic unit 374 is provided on one side (the side parallel to the second direction) of the groove 372 constituting the connecting portion 37, which elastically fits tightly against the protrusion 370 inserted into such groove 372.

[0113] In this case, due to the elasticity of the elastic unit 374, the surface of the protrusion 370 located on the opposite side of the surface in contact with the elastic unit 374 remains in close contact with the other side of the groove 372, thus suppressing the movement of the protrusion 370 in the first direction and allowing the protrusion 370 to move only in the second direction.

[0114] like Figure 6 As illustrated in (a), the elastic element 374 is preferably a leaf spring 374a that applies an elastic force to the protrusion 370 within the groove 372 in a manner that is tightly attached to the other side of the groove 372 opposite to one side of the protrusion 370. Depending on the situation, such as Figure 6 As shown in (b), the elastic unit 374 can also be in the form of a positioning ball plug 374b, which is composed of a ball and a spring.

[0115] On the other hand, at least two Hall sensors 308 are aligned and spaced apart in a first direction at the openings 303 and 305 of the aforementioned first sidewall 302 and second sidewall 304. Furthermore, Hall magnets 344 (see reference) are mounted on the side of the first movable portion 34a opposite the first sidewall 302 and the side of the second movable portion 34b opposite the second sidewall 304, corresponding to the Hall sensors 308. Figures 1 to 2 ).

[0116] The Hall sensor 308 uses the Hall effect to detect the position of the Hall magnet 344 and generates a corresponding signal to output to the driver IC (not shown). The driver IC identifies the position of the first movable part 34a and the second movable part 34b in a first direction within the housing 30 based on the signal from the Hall sensor 308. Furthermore, it determines the control value for the first drive part 32a and the second drive part 32b based on the identified position value.

[0117] That is, the driver IC identifies the correct position of the first movable part 34a and the second movable part 34b in the first direction based on the signal output by the Hall sensor 308, and determines the control value of the first drive part 32a and the second drive part 32b based on the identified position information. Based on the determined control value, the first drive part 32a and the second drive part 32b are used to independently feed back control the position of the first movable part 34a and the second movable part 34b in the first direction, thereby realizing zoom and autofocus.

[0118] Figure 7 The above is observed along the direction of line AA. Figure 3 The image shows a cross-sectional view of the camera actuator.

[0119] Reference Figure 7 and the above Figures 1 to 2 A ball guide 38 is provided between the outer casing 30 and the first movable part 34a and the second movable part 34b. The ball guide 38 serves to align the optical axes of the first movable part 34a and the second movable part 34b, while also guiding them between the outer casing 30 and the first movable part 34a and the second movable part 34b to stably achieve independent linear motion (translational motion) of the first movable part 34a and the second movable part 34b relative to the outer casing 30 in a first direction.

[0120] Preferably, the ball guide 38 is composed of the following components: a pair of parallel ball guide rails 380, which are arranged to extend along a first direction on the upper surface of the bottom of the housing 30 and have a first ball groove 382 that is continuous in the first direction on the upper surface portion; a second ball groove 384, which is formed on one side of the lower surface of the first movable portion 34a and the second movable portion 34b respectively and on the other side as opposite portions, corresponding to the first ball groove 382; and a ball 383, which is sandwiched between the first ball groove 382 and the second ball groove 384 that are opposite to each other.

[0121] If we observe the movable part 34 from the bottom, we can observe the carrier 340 more specifically. Figure 8 As shown, at least two second ball grooves 384 are formed in a pocket type, with independent spatial configurations on one side of the lower surface of the carrier 340 of each of the first movable part 34a and the second movable part 34b, and on the other side as opposing parts. Each second ball groove 384, formed in such an independent spatial configuration, holds one ball, thereby preventing interference or friction between adjacent balls 383 when the movable part 34 moves.

[0122] Here, considering the assemblability and drivability based on the manufacturing tolerances between the carrier 340 and the housing 30, specifically the movable part 34, it is preferable that one of the parallel pair of ball guides 380 has a first ball groove 382 continuously connected in the first direction configured as a V-groove, and the other ball guide has a first ball groove 382 configured as a U-groove.

[0123] Each ball 383 is configured such that a portion is housed in the first ball groove 382 and another portion is housed in the second ball groove 384. Thus, when the second ball groove 384 moves relative to the first ball groove 382 due to the linear movement of the movable part 34 in the first direction, the balls roll between these ball grooves (382, 384), thereby enabling the linear movement of the movable part 34 in the first direction to be realized slowly and stably within the housing 30.

[0124] like Figure 7 and Figure 8 As illustrated, magnets 341 are mounted on the lower surfaces of the first movable part 34a and the second movable part 34b, which are opposite to the upper surface of the bottom of the housing 30. All or part of the housing 30 (the bottom) is composed of a magnetic material. In this case, the first movable part 34a and the second movable part 34b move in close contact with the bottom side of the housing 30, separated by the aforementioned ball guide 38, due to the attraction between the bottom of the housing 30 and the magnets. This prevents the movable parts 34 from floating or tilting during movement.

[0125] Unspecified reference numeral 39 refers to a fixed optical unit (see figure). Figures 1 to 3 Such a fixed optical unit 39 is shown in the figure. Figures 1 to 3 An example of this configuration is shown at the opening on one side of the housing 30 where light flows in, and includes a lens barrel for housing a lens group consisting of multiple lenses. In this case, each of the lenses possesses the same or different optical characteristics such as focal length and refractive index.

[0126] In the case of conventional piezoelectric camera actuators developed as a countermeasure to the stepping motor method, if the vibration shaft deviates even slightly from the parallel state of the guide pin, or if the vibration shaft bends even slightly during vibration, the movable parts of the optical system may be trapped between the guide pin and the vibration shaft, resulting in unsmooth movement or even a complete inability to move.

[0127] Conversely, in the camera actuator of the embodiment of the present invention, even if the alignment of the vibration shaft (or movable part) in the first direction deviates to some extent during the assembly process, or if the vibration shaft bends during vibration and the gap between the movable part and the friction moving part changes, the gap change can be addressed by the connecting part, so the movable part is completely unaffected and moves smoothly in the first direction.

[0128] That is, it can accurately and clearly eliminate the problem of the previous technology that affects the mobility of the movable part (the problem that the movable part cannot move smoothly or becomes immobile in the first direction) caused by the misalignment of the vibration shaft (or the movable part) or the bending of the vibration shaft, etc. (the problem that the gap between the two needs to be kept uniform throughout the entire range of movement (Stroke) of the movable part).

[0129] Furthermore, the piezoelectric method, which is more compact and lightweight than conventional stepper motors, has a simple structure and is easy to assemble, thus offering advantages in mass production. Moreover, by using a magnet mounted on the lower surface of the movable part, the movable part can move smoothly and stably in a straight line through a ball guide when it is pressed tightly against the bottom side of the housing, eliminating the need for a separate guide pin for optical axis alignment.

[0130] on the other hand, Figure 9 This is a schematic diagram of a light-refracting camera module that includes one aspect of the camera actuator mentioned above.

[0131] Reference Figure 9 Another aspect of the present invention is a light-refracting camera module, which generally comprises a reflection system 2, a camera actuator 3, and an image sensor unit 5. The camera actuator 3 may be the camera actuator 3 of the above-described aspect, and the reflection system 2 is arranged in front of the camera actuator with reference to the direction of light travel to reflect externally incident light toward the camera actuator 3.

[0132] The reflection system 2 can be a mirror or prism that reflects light incident from the outside at a specific angle, preferably 45 degrees. The camera actuator 3 is configured such that two or more movable parts (34a, 34b) constituting the camera actuator 3 perform independent actions in a first direction through driving parts configured accordingly.

[0133] In this way, when two or more movable parts (34a, 34b) perform independent actions, they can zoom in and zoom out over a wide range, achieving more precise, detailed and high-magnification zoom performance.

[0134] The image sensor unit 5 receives light passing through the movable part of the camera actuator 3 and outputs image information corresponding to the received light. Such an image sensor unit 5 consists of a substrate 52 and an image sensor 50 mounted on the substrate 52. The image sensor 50 collects image information based on the light passing through the movable parts (34a, 34b) and outputs the collected image information to the outside through the substrate 52.

[0135] An IR filter 4 is disposed in the optical path between the camera actuator 3 and the image sensor unit 5. The IR filter 4 filters out specific wavelengths, preferably infrared wavelengths, included in the incident light, so as to project the infrared-filtered light onto the image sensor module 5. The accompanying drawings illustrate an example of IR filter 4 being disposed between the camera actuator 3 and the image sensor module 5, but are not limited to this.

[0136] The specific embodiments described above are merely particular examples. However, the invention is not limited to the particular forms mentioned in the specific embodiments, but includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims.

[0137] Explanation of reference numerals in the attached figures

[0138] 1: Camera module; 2: Reflection system

[0139] 3: Camera actuator 4: IR filter

[0140] 5: Image sensor unit 20: Reflective surface

[0141] 30: Outer casing; 32: Drive unit

[0142] 32a: First drive unit; 32b: Second drive unit

[0143] 34: Movable part 34a: First movable part

[0144] 34b: Second movable part; 36: Friction moving part

[0145] 37: Connecting part; 38: Ball guide component

[0146] 39: Fixed optical unit; 50: Image sensor

[0147] 52: Substrate; 302, 304: Sidewalls of the casing

[0148] 303, 305: Openings; 308: Hall sensor

[0149] 309: Support component; 320: Vibration shaft

[0150] 322: Vibration generator; 340: Carrier

[0151] 341: Magnet; 342: Lens barrel

[0152] 344: Hall magnet; 370: Protrusion

[0153] 371: Thin plate; 372: Groove

[0154] 374: Elastic element; 374a: Leaf spring

[0155] 374b: Positioning ball plug; 380: Ball guide rail

[0156] 382: First ball groove; 383: Ball.

[0157] 384: Second ball groove.

Claims

1. A camera actuator, comprising: shell; Two or more movable parts are mounted on the aforementioned housing and are driven independently of each other along a first direction to achieve zooming and autofocus; and Two or more drive units are mounted on the aforementioned housing and are equipped with piezoelectric elements for driving each of the aforementioned movable units in a first direction. The piezoelectric elements are arranged diagonally opposite each other with respect to an axis passing through the center of the movable part in a first direction. The movable part is equipped with a ball guide that supports the movable part so that the movable part can roll in the first direction. The aforementioned camera actuator also includes: The friction moving part moves in a first direction along a vibration axis connected to the piezoelectric element described above; and A connecting part that connects the aforementioned friction-moving part and the aforementioned movable part to each other. The aforementioned connecting portion is composed of a protrusion or groove formed on the side surface of the friction moving portion opposite to the aforementioned movable portion, and a groove or protrusion formed on the side surface of the aforementioned movable portion in a manner that engages with the aforementioned protrusion or groove. The aforementioned connecting portion inhibits the movement of the aforementioned protrusion or groove in the first direction and allows the aforementioned protrusion or groove to move in a second direction orthogonal to the first direction.

2. A camera actuator, comprising: shell; The drive unit is mounted on the aforementioned housing and consists of a vibration shaft extending in a first direction and a vibration generator that applies vibration to the aforementioned vibration shaft in the first direction. A movable part is provided corresponding to the aforementioned drive part, and moves within the housing in a first direction by the driving force generated by the aforementioned drive part; The friction moving part moves in a first direction on the aforementioned vibration shaft; and The connecting part connects the aforementioned friction-moving part and the movable part to each other. The aforementioned connecting portion is composed of a protrusion or groove formed on the side surface of the friction moving portion opposite to the aforementioned movable portion, and a groove or protrusion formed on the side surface of the aforementioned movable portion in a manner that engages with the aforementioned protrusion or groove. The aforementioned connecting portion inhibits the movement of the aforementioned protrusion or groove in the first direction and allows the aforementioned protrusion or groove to move in a second direction orthogonal to the first direction.

3. The camera actuator according to claim 2, wherein, The aforementioned protrusions are magnets. A thin plate of magnetic material is attached to one side of the groove to generate attraction between the protrusion formed by the magnet and the groove, so as to suppress the movement of the protrusion in the first direction and allow the protrusion to move in the second direction orthogonal to the first direction within the grooved area.

4. The camera actuator according to claim 2, wherein, The aforementioned protrusions are made of a magnetic material. A thin plate magnet is attached to one side of the groove. The thin plate magnet generates an attraction between itself and the protrusion of the magnetic material, so as to suppress the movement of the protrusion in a first direction and allow the protrusion to move in a second direction orthogonal to the first direction within the grooved area.

5. The camera actuator according to claim 2, wherein, An elastic element is provided on one side of the groove, which is elastically attached to the protrusion, so as to suppress the movement of the protrusion in the first direction within the grooved area and allow the protrusion to move in a second direction orthogonal to the first direction.

6. The camera actuator according to claim 5, wherein, The aforementioned elastic unit is a leaf spring that applies elastic force to the protrusion by being in close contact with the other side of the groove opposite to one side of the protrusion, or a positioning ball plug composed of a ball and a spring.

7. The camera actuator according to claim 2, wherein, The aforementioned drive unit is configured to consist of two or more units. The movable part is configured in two or more parts so as to correspond one-to-one with the two or more drive parts.

8. The camera actuator according to claim 7, wherein, The aforementioned drive unit consists of a first drive unit and a second drive unit. The aforementioned first drive unit is mounted adjacent to the first sidewall of the housing and comprises a vibration shaft extending in a first direction and a vibration generator that applies vibration to the vibration shaft in the first direction. The second drive unit is mounted adjacent to the second sidewall in the housing, and has the same structure as the first drive unit but with the vibration generator positioned opposite to it. The second sidewall is opposite to the first sidewall. The aforementioned movable part is composed of a first movable part and a second movable part. The first movable part moves in a first direction within the outer casing by the driving force generated by the first driving part. The second movable part is arranged coaxially with the first movable part in the first direction within the housing, and moves in translation in the first direction within the housing by the driving force generated by the second driving part.

9. The camera actuator according to claim 7, wherein, Each of the aforementioned two or more movable parts is driven independently in the first direction via a corresponding drive unit.

10. The camera actuator according to claim 8, wherein, At least two Hall sensors are spaced apart and aligned in a first direction on each of the first sidewall and the second sidewall, which are opposite portions of the aforementioned housing. Hall magnets are mounted on the side of the first movable part opposite to the first sidewall and on the side of the second movable part opposite to the second sidewall, corresponding to the Hall sensor.

11. The camera actuator according to claim 2, wherein, The aforementioned movable parts include: carrier; and The lens barrel is mounted on the aforementioned carrier and houses a lens group consisting of multiple lenses.

12. The camera actuator according to claim 2, wherein, The vibration generator of the aforementioned drive unit is a piezoelectric motor that includes a piezoelectric element.

13. The camera actuator according to claim 2, wherein, The aforementioned friction moving part consists of a lower friction block and an upper friction clamp. The aforementioned lower friction block has a groove with a cross-section shaped like an arc or an angle. The aforementioned upper friction clamp is connected to the upper part of the aforementioned lower friction block with the aforementioned vibration shaft in between. Its cross-sectional shape is the same as the shape of the aforementioned groove and is symmetrical to the groove vertically.

14. The camera actuator according to claim 2, further comprising: A ball guide guides the translational movement of the movable part relative to the housing in a first direction between the housing and the movable part.

15. The camera actuator according to claim 14, wherein, The aforementioned ball guide is composed of the following components: A pair of ball guides, which are arranged to extend along the first direction on the bottom upper surface of the housing and have a first ball groove continuously formed in the first direction; The second ball groove is formed on one side of the lower surface of the movable part and on the other side of the opposite part in a manner corresponding to the first ball groove described above. and The ball is sandwiched between a first ball groove and a second ball groove that are opposite to each other.

16. The camera actuator according to claim 15, wherein, The aforementioned second ball grooves are formed in a bag-like shape on one side of the lower surface of the movable part and on the other side of the opposite part, with independent spatial forms, at least two in total. Each of the second ball grooves, which are formed in an independent spatial form, holds a ball.

17. The camera actuator according to claim 14, wherein, The aforementioned outer shell is made of a magnetic material. A magnet is mounted on the lower surface of the movable part, which is opposite to the upper surface of the bottom of the aforementioned outer casing.

18. A light refraction camera module, comprising: The camera actuator as described in claim 1 or 2; A reflection system is positioned in front of the camera actuator based on the direction of light travel, reflecting externally incident light toward the camera actuator. and An image sensor unit is positioned behind the camera actuator with the direction of light propagation as a reference. It receives light passing through the camera actuator and generates and outputs corresponding image information based on the received light.

Images