Lens driving device

Abstract

This embodiment relates to a lens driving device, which includes: a lens barrel; a lens disposed in the lens barrel; and a driving unit disposed in the lens barrel, wherein: the driving unit includes a piezoelectric element, a first component, and a second component; when a voltage is applied to the piezoelectric element, the piezoelectric element extends or contracts in a direction perpendicular to the optical axis of the lens; the first component is disposed on the piezoelectric element; and the second component is connected to the first component and disposed in the lens barrel; when a voltage is applied to the piezoelectric element, the lens barrel moves in the optical axis direction of the lens; and the first length in the longitudinal direction of the first component is shorter than the second length in the longitudinal direction of the second component.

Description

Technical Field

[0001] This embodiment relates to a lens driving device. Background Technology

[0002] Portable devices, such as tablets or smartphones, are equipped with camera modules that acquire image information from objects. There is an increasing need for camera modules in such portable devices that offer high pixel density and high performance, and recently, products capable of autofocus (AF) and optical zoom, where the focal length can be changed, have been released.

[0003] Typically, the camera module in a portable device moves the lens along the optical axis to adjust autofocus and / or optical zoom. To move the lens, a voice coil motor (VCM) type actuator is widely used, which utilizes electromagnetic force to move the lens by placing a coil and a magnet in the camera module.

[0004] However, due to the weak driving force of the actuators in existing VCM methods, it is difficult to achieve long strokes for high magnification zoom.

[0005] Furthermore, when increasing the stroke length of existing VCM actuators for high-magnification zoom control, the size of the coils and magnets also increases, making it difficult to miniaturize the camera module.

[0006] In addition, existing VCM actuators have the problem of consuming unnecessary power due to magnetic field interference from the magnet. Summary of the Invention

[0007] Technical topics

[0008] This embodiment provides a lens driving device that can achieve long stroke using piezoelectric elements.

[0009] Another object of the present invention is to provide a lens driving device that can rapidly drive a lens group with high magnification and high weight by means of a driving unit using the lever principle.

[0010] Technical solution

[0011] The lens driving device according to this embodiment includes: a lens barrel; a lens disposed in the lens barrel; and a driving unit disposed in the lens barrel. The driving unit includes a piezoelectric element, a first component, and a second component. When a voltage is applied to the piezoelectric element, the piezoelectric element elongates or contracts in a direction perpendicular to the optical axis of the lens. The first component is disposed in the piezoelectric element, and the second component is connected to the first component and disposed in the lens barrel. When a voltage is applied to the piezoelectric element, the lens barrel moves in the optical axis direction of the lens. The first length of the first component in the longitudinal direction is shorter than the second length of the second component in the longitudinal direction.

[0012] Furthermore, the first angle formed by the first component and the second component can be changed when a voltage is applied to the piezoelectric element.

[0013] Furthermore, in the initial state where no voltage is applied to the piezoelectric device, the first angle formed by the first member and the second member can be smaller than the second angle formed by the first member and the second member when voltage is applied to the piezoelectric device.

[0014] Furthermore, the first and second components can be hinged together.

[0015] Furthermore, the distance the lens barrel moves along the optical axis can be determined by the ratio between the first length of the first component and the second length of the second component.

[0016] Furthermore, the distance the lens barrel moves along the optical axis can be determined by the number of second components.

[0017] In addition, the lens driving device includes a housing disposed on the outside of the lens barrel; the housing includes an upper plate and a first side plate to a fourth side plate extending from the upper plate; and the driving unit may be disposed in the first side plate of the housing.

[0018] Furthermore, the lens driving device includes a third component and a fourth component, the third component being configured to intersect with the first component, and the fourth component being connected to the third component and configured to intersect with the second component; the first side plate of the housing includes a slit extending in the optical axis direction; and each of the first intersection point of the first component and the third component and the second intersection point of the second component and the fourth component can be located in the slit of the first side plate of the housing.

[0019] In addition, the lens driving device includes a first pin and a second pin. The first pin is disposed in the lens barrel, and the second pin is disposed in the lens barrel and spaced apart from the first pin. The first pin and the second pin can guide the movement of the lens barrel in the optical axis direction.

[0020] In addition, the lens driving device may include electrodes and sensors, with the electrodes disposed between the lower portion of the piezoelectric element and the first member, and the sensors spaced apart from the electrodes.

[0021] Furthermore, the separation distance between the electrode and the sensor in the direction perpendicular to the optical axis includes a first separation distance in the initial state when no voltage is applied to the piezoelectric element; when voltage is applied to the piezoelectric element, the first separation distance is changed to a second separation distance in the direction perpendicular to the optical axis, and the second separation distance is smaller than the first separation distance; and when voltage is applied to the piezoelectric element, the lens barrel can move away from the piezoelectric element in the direction of the optical axis.

[0022] In addition, the lens driving device may include electrodes and sensors, with the electrodes disposed in a first component and the sensors disposed in a second component and overlapping the electrodes in the optical axis direction.

[0023] Furthermore, the separation distance between the electrode and the sensor in the optical axis direction includes a third separation distance in the initial state when no voltage is applied to the piezoelectric element; when voltage is applied to the piezoelectric element, the third separation distance in the optical axis direction is changed to a fourth separation distance, which is greater than the third separation distance; and when voltage is applied to the piezoelectric element, the lens barrel can move away from the piezoelectric element in the optical axis direction.

[0024] The camera module according to this embodiment may include a lens driving device.

[0025] Beneficial effects

[0026] This embodiment can provide a lens driving device that can use piezoelectric elements to achieve long strokes.

[0027] In addition, a lens driving device can be provided that can rapidly drive a high-magnification and heavy lens group by means of a drive unit using the lever principle.

[0028] In addition, it can provide lens drive devices that move 10 times or more faster than conventional VCM type actuators. Attached Figure Description

[0029] Figure 1 This is a perspective view of a lens driving device according to a first embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of a lens driving device according to a first embodiment of the present invention.

[0031] Figure 3 This is a diagram showing the second length of the second component of the lens driving device according to the first embodiment of the present invention, and the distance the lens barrel moves in the optical axis direction.

[0032] Figure 4 This is a schematic diagram of a lens driving device according to a second embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram of a lens driving device according to a third embodiment of the present invention. Detailed Implementation

[0034] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings.

[0035] However, the technical concept of the present invention is not limited to the few embodiments described, but can be implemented in various forms, and within the scope of the technical concept of the present invention, one or more of the constituent elements can be selectively combined or substituted among the embodiments.

[0036] Furthermore, unless explicitly defined and described, the terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having meanings that are commonly understood by those skilled in the art, and commonly used terms, such as those defined in dictionaries, may be interpreted in the context of the relevant art.

[0037] Furthermore, the terminology used in this specification is for describing embodiments and is not intended to limit the invention.

[0038] In this specification, unless specifically stated in the phrase, the singular form may include the plural form, and when described as “at least one (or more than one) of A, B and C”, it may include one or more of all combinations that can be combined with A, B and C.

[0039] Furthermore, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended only to distinguish components from other components, and they do not limit the nature, order, or sequence of the components.

[0040] Furthermore, when a component is described as being “connected,” “linked,” or “interconnected” to another component, the component is not only directly connected, linked, or interconnected to another component, but may also include situations where the “connection,” “linking,” or “interconnection” is made due to another component between other components.

[0041] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" means not only that the two components are in direct contact, but also that one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," it can include not only the meaning of an upward direction based on a component, but also the meaning of a downward direction based on a component.

[0042] In the following description, the configuration of the lens driving device according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0043] Figure 1 This is a perspective view of a lens driving device according to a first embodiment of the present invention; and Figure 2 This is a schematic diagram of a lens driving device according to a first embodiment of the present invention.

[0044] The lens driving device according to a first embodiment of the present invention may include a housing 100. The housing 100 may form the appearance of the lens driving device. The housing 100 may be formed in a hexahedral shape having an open lower surface.

[0045] The housing 100 may be disposed on the outside of the lens barrel 200. The housing 100 may accommodate the lens barrel 200. The housing 100 may be formed of an insulating material. The housing 100 may be formed of an injection molding material. The housing 100 may include an upper plate 110 and a side plate 120 extending from the upper plate 110. The side plate 120 may extend downward from the edge of the upper plate 110 of the housing 100. The side plate 120 may include a first side plate 121, a second side plate 122, a third side plate disposed on the opposite side of the first side plate 121, and a fourth side plate disposed on the opposite side of the second side plate. A driving unit 300 may be disposed in the first side plate 121. The driving unit 300 may be disposed between the first side plate 121 and the lens barrel 200. A slit 123 may be formed in the first side plate 121.

[0046] The housing 100 may include four side portions and four corner portions disposed between the four side portions. The side portions of the housing 100 may include a first side portion, a second side portion, a third side portion disposed on the opposite side of the first side portion, and a fourth side portion disposed on the opposite side of the second side portion. The corner portions of the housing 100 may include: a first corner portion disposed between the first side portion and the second side portion; a second corner portion disposed between the second side portion and the third side portion; a third corner portion disposed between the third side portion and the fourth side portion; and a fourth corner portion disposed between the fourth side portion and the first side portion. The side portions of the housing 100 may include "sidewalls".

[0047] The housing 100 may include a slit 123. The slit 123 may be formed in the first side plate 121. The slit 123 may be a hole penetrating the first side plate 121 in a direction perpendicular to the optical axis. The slit 123 may be formed along the longitudinal direction of the first side plate 121. The slit 123 may be formed in the first side plate 121 along the optical axis. A third hinge portion 380 may be provided in the slit 123, in which the first member 320 and the third member 250 intersect. A fourth hinge portion 390 may be provided in the slit 123, in which the second member 330 and the fourth member 360 intersect. The slit 123 may be a passageway through which the third hinge portion 380 and the fourth hinge portion 390 move in the optical axis direction. When the third hinge portion 380 and the fourth hinge portion 390 move in the optical axis direction, the slit 123 may reduce the frictional force with the first side plate 121.

[0048] The lens driving device according to a first embodiment of the present invention may include a lens barrel 200. The lens barrel 200 may be disposed inside the housing 100. The lens barrel 200 may be disposed below the upper plate 110 of the housing 100. The lens barrel 200 may be disposed inside the side plate 120 of the housing 100. The lens barrel 200 may include a lens. The lens barrel 200 may include multiple lenses. The lens barrel 200 may include holes for receiving lenses. The lens barrel 200 may be moved in the optical axis direction of the lens by a driving unit 300. Thus, an autofocus function can be performed. Additionally, zooming can be performed.

[0049] The lens barrel 200 can be formed in a hexahedral shape. The lens barrel 200 can also be formed with a rectangular cross-section. The lens barrel 200 may include: a first side portion; a second side portion; a third side portion disposed on the opposite side of the first side portion; and a fourth side portion disposed on the opposite side of the second side portion. The lens barrel 200 may include: a first corner portion disposed between the first and second side portions; a second corner portion disposed between the second and third side portions; a third corner portion disposed between the third and fourth side portions; and a fourth corner portion disposed between the fourth and first side portions. In the above description, the lens barrel 200 has been described based on the premise that it has a hexahedral shape; however, the present invention is not limited thereto, and the lens barrel 200 may also be formed in a cylindrical shape, etc.

[0050] A drive unit 300 may be disposed within the lens barrel 200. The drive unit 300 may be disposed within a first side portion of the lens barrel 200. A second member 330 may be disposed within the first side portion of the lens barrel 200. A first connecting member 332 may be disposed within the first side portion of the lens barrel 200. In this case, the second member 330 may not be disposed within the first side portion of the lens barrel 200. A fourth member 360 may be disposed within the first side portion of the lens barrel 200. The lens barrel 200 may move in the optical axis direction by the movement of at least one of the second member 330 and the fourth member 360. When a voltage is applied to the piezoelectric element 310, the lens barrel 200 may move in the optical axis direction of the lens.

[0051] The lens driving device according to a first embodiment of the present invention may include a driving unit 300. The driving unit 300 may be disposed in the lens barrel 200. The driving unit 300 may be disposed in a first side portion of the lens barrel 200. The driving unit 300 may be disposed in a first side plate 121 of the housing 100. The driving unit 300 may be disposed between the first side portion of the lens barrel 200 and the first side plate 121 of the housing 100.

[0052] The drive unit 300 may include a piezoelectric element 310. The piezoelectric element 310 may be piezoelectric in nature. The piezoelectric element 310 can generate power to move the lens barrel 200 in the optical axis direction. When a voltage is applied, the piezoelectric element 310 can elongate or contract in its longitudinal direction. When a voltage is applied, the piezoelectric element 310 can elongate or contract in a direction perpendicular to the optical axis. When a voltage is applied causing the piezoelectric element 310 to elongate in a first direction perpendicular to the optical axis, the piezoelectric element 310 elongates in the first direction to press one end of the first member 320. When a voltage is applied causing the piezoelectric element 310 to contract in a second direction perpendicular to the optical axis and opposite to the first direction, the length of the piezoelectric element 310 can be shortened to its original state. At this time, the first member 320 can also return to its original position.

[0053] The drive unit 300 may include a first component 320. The first component 320 may be disposed within the piezoelectric element 310. The first component 320 may be a component for transmitting power generated by the piezoelectric element 310. The first component 320 may be disposed at the lower portion of the piezoelectric element 310. The first component 320 may be connected to a second component 320. One end of the first component 320 may be disposed within the piezoelectric element 310 and the other end may be connected to the second component 320. The first component 310 may be hingedly connected to the second component 320. A first hinge portion 340 may be provided at the other end of the first component 310.

[0054] The first component 320 may have a first length L1 in its longitudinal direction. The first length L1 of the first component 320 may be shorter than the second length L2 of the second component 330 in its longitudinal direction. The ratio between the first length L1 of the first component 320 and the second length L2 of the second component 330 may be one of 1:2, 1:3, and 1:4. That is, when the first length L1 is 1 mm, the second length L2 may be 2 mm. When the first length L1 is 1 mm, the second length L2 may be 3 mm. When the first length L1 is 1 mm, the second length L2 may be 4 mm. In this case, the moving distance of the lens barrel 200 in the optical axis direction can be determined by the ratio between the first length L1 of the first component 320 and the second length L2 of the second component 330. The driving energy used to move the lens barrel 200 may be inversely proportional to the ratio between the first length L1 of the first component 320 and the second length L2 of the second component 330. In other words, when the second length L2 of the second member 330 increases relative to the first length L1 of the first member 320, the driving energy required to move the lens barrel 200 can be reduced.

[0055] The drive unit 300 may include a second component 330. The second component 330 may be a component for transmitting power generated by the piezoelectric element 310. The second component 330 may be coupled to the first component 320. The second component 330 may be disposed within the lens barrel 200. One end of the second component 330 may be coupled to the first component 320, and the other end may be disposed within a first side portion of the lens barrel 200. Alternatively, one end of the second component 330 may be coupled to the first component 320, and the other end may be coupled to a first connecting member 332. In this case, the second component 330 may not be disposed within the first side portion of the lens barrel 200. The second component 330 may be hinged to the first component 320. A first hinge portion 340 may be disposed at one end of the second component 330. The second component 330 may rotate relative to the first component 320 about the first hinge portion 340. When the piezoelectric element 310 extends in a first direction to press the first component 320, the second component 330 may rotate about the first hinge portion 340. In this case, the other end of the first component 320 and one end of the second component 330 move in the optical axis direction, and the lens barrel 200 can move a corresponding displacement in the optical axis direction together with the first component 320 and the second component 330.

[0056] The drive unit 300 may include a first connecting member 332. The first connecting member 332 may be disposed within the lens barrel 200. The first connecting member 332 may be disposed in a first side portion of the lens barrel 200. One end of the first connecting member 332 may be disposed in the first side portion of the lens barrel 200, and the other end may be connected to a second member 330. The first connecting member 332 may be disposed between the lens barrel 200 and the second member 330. In this case, the first connecting member 332 can receive power from the piezoelectric element 310 transmitted from the second member 330 to move the lens barrel 200 in the optical axis direction.

[0057] The second component 330 may include multiple second components 330. The movement distance of the lens barrel in the optical axis direction can be determined by the number of second components 330. When the number of second components 330 increases, the movement distance of the lens barrel 200 in the optical axis direction can increase. In this case, a long stroke can be achieved. Specifically, a stroke distance of 6 mm or greater can be ensured. For example, to ensure a stroke distance of 6 mm or greater, four second components 330 may be required in a structure where the first length L1 of the first component 320 is 1 mm and the second length L2 of the second component 330 is 3 mm. Furthermore, three second components 330 may be required in a structure where the first length L1 of the first component 320 is 1 mm and the second length L2 of the second component 330 is 4 mm. However, the invention is not limited thereto, and the first length L1 of the first component 320, the second length L2 of the second component 330, and the number of second components 330 can be determined according to the stroke distance required for zooming.

[0058] The first member 320 and the second member 330 can be configured in a Z-shape. The first member 320 and the second member 330 can be moved using the lever principle with the first hinge 340 as a fulcrum. This allows for a long stroke with very little force. Furthermore, when the first member 320 and the second member 330 are configured in a Z-shape, a long stroke can be achieved, and the height of the lens drive device in the optical axis direction can be minimized. The first angle θ1 formed by the first member 320 and the second member 330 can be changed when voltage is applied to the piezoelectric element 310. In the initial state where voltage is not applied to the piezoelectric element 310, the first angle θ1 formed by the first member 320 and the second member 330 can be smaller than the second angle θ3 formed by the first member 320 and the second member 330 when voltage is applied to the piezoelectric element 310, causing the piezoelectric element 310 to elongate in the first direction.

[0059] The drive unit 300 may include a third member 350. The third member 350 may be configured to intersect with the first member 320. The third member 350 may include a first intersection point at the portion where it intersects with the first member 320. The third member 350 may be connected to the first member 320 at the first intersection point. The third member 350 may be hingedly connected to the first member 320. The third member 350 may include a third hinge portion 380 located at the first intersection point. The third hinge portion 380 may be disposed in a slit 123 of the first side plate 121 of the housing 100. At least a portion of the third hinge portion 380 may be disposed inside the slit 123 of the first side plate 121 of the housing 100. The third member 350 may rotate relative to the first member 320 about the third hinge portion 380. That is, when the first member 320 is pressed by the piezoelectric element 310, the third hinge portion 380 may move in a direction toward the upper plate 110 of the housing 100. The third component 350 can move in a direction opposite to the direction of movement of the first component 320. That is, when the first component 320 moves in a first direction, the third component 350 can move in a second direction opposite to the first direction. When the first component 320 moves in the second direction, the third component 350 can move in the first direction. Thus, even with a small amount of power, the moving speed of the lens barrel 200 in the optical axis direction can be increased.

[0060] The third member 350 may have the same length in the longitudinal direction as the first member 320 (L1). The third member 350 may be arranged parallel to the second member 330. The third length of the third member 350 may be shorter than the second length (L2) of the second member 330. The third length of the third member 350 may be shorter than the fourth length of the fourth member 360. One end of the third member 350 may be connected to the fourth member 360. One end of the third member 350 may be hinged to the fourth member 360. In this case, a second hinge portion 370 may be provided at one end of the third member 350.

[0061] The drive unit 300 may include a fourth member 360. The fourth member 360 may be configured to intersect with the second member 330. The fourth member 360 may include a second intersection point at its intersection with the second member 330. The fourth member 360 may be connected to the second member 330 at the second intersection point. The fourth member 360 may be hingedly connected to the first member 320. The fourth member 360 may include a fourth hinge portion 390 located at the second intersection point. The fourth hinge portion 390 may be disposed in a slit 123 of the first side plate 121 of the housing 100. At least a portion of the fourth hinge portion 390 may be disposed inside the slit 123 of the first side plate 121 of the housing 100. The fourth hinge portion 390 may overlap with a third hinge portion 380 in the optical axis direction. The fourth member 360 may rotate relative to the second member 330 about the fourth hinge portion 390. In other words, when the first member 320 is pressed by the piezoelectric element 310, the fourth hinge portion 390 can move in the direction pointing towards the upper plate 110 of the housing 100. The fourth member 360 can move in the opposite direction to the movement direction of the second member 330. That is, when the second member 330 moves in the first direction, the fourth member 360 can move in the second direction opposite to the first direction. When the second member 330 moves in the second direction, the fourth member 360 can move in the first direction. Thus, even with a small amount of power, the movement speed of the lens barrel 200 in the optical axis direction can be increased.

[0062] The drive unit 300 may include a fourth component 360. The fourth component 360 may be a component for transmitting power generated by the piezoelectric element 310. The fourth component 360 may be coupled to the third component 350. The fourth component 360 may be disposed within the lens barrel 200. One end of the fourth component 360 may be coupled to the third component 350, and the other end may be disposed within a first side portion of the lens barrel 200. Alternatively, one end of the fourth component 360 may be coupled to the third component 350, and the other end may be coupled to the connecting member 362. In this case, the fourth component 360 may not be disposed within the first side portion of the lens barrel 200. The fourth component 360 may be hinged to the third component 350. A second hinge portion 370 may be disposed at one end of the fourth component 360. The fourth component 360 may rotate relative to the first component 320 about the second hinge portion 370. When the piezoelectric element 310 extends in the first direction to press the first member 320, the fourth member 360 can rotate about the second hinge portion 370. In this case, one end of the fourth member 360 can move in the optical axis direction, and the lens barrel 200 can move a corresponding displacement in the optical axis direction together with the fourth member 360.

[0063] The drive unit 300 may include a connecting member 362. The second connecting member 362 may be disposed within the lens barrel 200. The second connecting member 362 may be disposed within a first side portion of the lens barrel 200. One end of the second connecting member 362 may be disposed within the first side portion of the lens barrel 200, and the other end may be connected to a fourth member 360. The second connecting member 362 may be disposed between the lens barrel 200 and the fourth member 360. In this case, the second connecting member 362 can receive power from the piezoelectric element 310 transmitted by the fourth member 360 to move the lens barrel 200 in the optical axis direction.

[0064] The fourth member 360 may have the same fourth length in the longitudinal direction as the second length L2 of the second member 330. The fourth member 360 may be arranged parallel to the first member 320. The fourth length of the fourth member 360 may be shorter than the first length L1 of the first member 320. The fourth length of the fourth member 360 may be shorter than the third length of the third member 350. One end of the fourth member 360 may be connected to the third member 350. One end of the fourth member 360 may be hinged to the third member 350. In this case, the second hinge portion 370 may be provided at one end of the fourth member 360. When the first member 320 and the second member 330 move, the third hinge portion 380 and the fourth hinge portion 390 may move along the slit 125 in the optical axis direction.

[0065] The lens driving device according to a first embodiment of the present invention may include a guiding unit 400. The guiding unit 400 may include a first pin 410. The first pin 410 may be disposed in the lens barrel 200. The first pin 410 may be spaced apart from a second pin 420. The first pin 410 may be disposed closer to the driving unit 300 than the second pin 420. The first pin 410 may guide the movement of the lens barrel 200 in the optical axis direction. One end of the first pin 410 may be disposed in the upper plate of the housing 100. The other end of the first pin 410 may be disposed in the lower plate of the housing 100. The first pin 410 may be disposed parallel to the second pin 420.

[0066] The guiding unit 400 may include a second pin 420. The second pin 420 may be disposed within the lens barrel 200. The second pin 420 may be spaced apart from the first pin 410. The second pin 420 may be positioned further from the driving unit 300 than the first pin 410. The second pin 420 may guide the movement of the lens barrel 200 in the optical axis direction. One end of the second pin 420 may be disposed in the upper plate of the housing 100. The other end of the second pin 420 may be disposed in the lower plate of the housing 100. The second pin 420 may be disposed parallel to the first pin 410.

[0067] Figure 3This is a graph showing the movement distance of the lens barrel in the optical axis direction based on the second length of the second member of the lens driving device according to the first embodiment of the present invention. The x-axis represents the number of second members 330, and the y-axis represents the movement distance (mm) of the lens barrel 200 in the optical axis direction. (a) is a linear graph when the second length L2 of the second member 330 is 2 mm, (b) is a linear graph when the second length L2 of the second member 330 is 3 mm, and (c) shows a linear graph when the second length L2 of the second member 330 is 4 mm.

[0068] [Table 1]

[0069]

[0070] Reference Figure 3 According to Table 1, when the second length L2 of the second component 330 is 2mm, it can be seen that a long stroke of 6mm can be achieved when there are 5 or more second components 330. It can also be seen that when the second length L2 of the second component 330 is 3mm, a long stroke of 6mm can be achieved when there are 4 or more second components 330.

[0071] In the following description, the configuration of the lens driving device according to the second embodiment of the present invention will be described with reference to the accompanying drawings.

[0072] Figure 4 This is a schematic diagram of a lens driving device according to a second embodiment of the present invention.

[0073] The lens driving device according to the second embodiment of the present invention can be interpreted as having the same configuration as the lens driving device according to the first embodiment, except for the sensor unit 500.

[0074] The lens driving device according to a second embodiment of the present invention may include a sensor unit 500. The sensor unit 500 may include a capacitive sensor. The sensor unit 500 can detect the movement of the first member 320. Therefore, the sensor unit 500 can control the movement distance of the lens barrel 200 in the optical axis direction.

[0075] The sensor unit 500 may include an electrode 510. The electrode 510 may be disposed at the lower portion of the piezoelectric element 310. The electrode 510 may be disposed at one end of the first member 320. The electrode 510 may be disposed between the piezoelectric element 310 and the first member 320. The electrode 510 may be spaced apart from the sensor 520.

[0076] Sensor unit 500 may include sensor 520. Sensor 520 may be spaced apart from electrode 510. Sensor 520 may overlap with electrode 510 in a direction perpendicular to the optical axis. Sensor 520 may be disposed in the first side plate 121 of housing 100. Sensor 520 may be disposed in the first side plate 121 of housing 100 to overlap with electrode 510 in a direction perpendicular to the optical axis.

[0077] The sensor value (C, capacitance value) of sensor unit 500 can be changed by the separation distance between sensor 520 and electrode 510 in the direction perpendicular to the optical axis. The sensor value C of sensor unit 500 can be inversely proportional to the separation distance between sensor 520 and electrode 510 in the direction perpendicular to the optical axis. The sensor value C of sensor unit 500 can be proportional to the area of ​​electrode 510. The sensor value C of sensor unit 500 can be determined by the following [conditional expression].

[0078] [Conditional Expression]

[0079] C = ε0 * ε r *A / d

[0080] Here, A represents the area of ​​electrode 510, d represents the separation distance between sensor 520 and electrode 510 in the direction perpendicular to the optical axis, and ε0 = 8.854 * 10 -12 , and ε r =1.

[0081] In the initial state where no voltage is applied to the piezoelectric element 310, the sensor unit 500 can have a first separation distance d1 between the sensor 520 and the electrode 510 in a direction perpendicular to the optical axis. When a voltage is applied to the piezoelectric element 310 to cause it to extend in the first direction perpendicular to the optical axis, the sensor unit 500 can have a second separation distance d2 between the sensor 520 and the electrode 510 in the same direction. The first separation distance d1 can be greater than the second separation distance d2.

[0082] In the following description, the configuration of the lens driving device according to the third embodiment of the present invention will be described with reference to the accompanying drawings.

[0083] Figure 5 This is a schematic diagram of a lens driving device according to a third embodiment of the present invention.

[0084] The lens driving device according to the third embodiment of the present invention can be interpreted as having the same configuration as the lens driving device according to the first embodiment, except for the sensor unit 500.

[0085] The lens driving device according to a third embodiment of the present invention may include a sensor unit 500. The sensor unit 500 may include a capacitive sensor. The sensor unit 500 can detect the movement of the first member 320. Therefore, the sensor unit 500 can control the movement distance of the lens barrel 200 in the optical axis direction.

[0086] The sensor unit 500 may include an electrode 510 and a sensor 520. The electrode 510 may be disposed in either the first member 320 or the second member 330. The sensor 520 may be disposed in either the first member 320 or the second member 330. When the electrode 510 is disposed in the first member 320, the sensor 520 is disposed in the second member 330, and when the electrode 510 is disposed in the second member 330, the sensor 520 may be disposed in the first member 320. However, the invention is not limited thereto, and the electrode 510 and the sensor 520 may be arranged to be spaced apart from each other in a plurality of second members 330. Hereinafter, it is assumed that the electrode 510 is disposed in the first member 320 and the sensor 520 is disposed in the second member 330.

[0087] Sensor 520 may be spaced apart from electrode 510. Sensor 520 may overlap with electrode 510 in the optical axis direction. At least a portion of sensor 520 may overlap with electrode 510 in the optical axis direction. Sensor 520 may be disposed in the second member 330 at a position overlapping with electrode 510 in the optical axis direction.

[0088] The sensor value (C, capacitance value) of sensor unit 500 can be changed according to the separation distance between sensor 520 and electrode 510 in the optical axis direction. The sensor value C of sensor unit 500 can be inversely proportional to the separation distance between sensor 520 and electrode 510 in the optical axis direction. The sensor value C of sensor unit 500 can also be proportional to the area of ​​overlap between electrode 510 and sensor 520 in the optical axis direction.

[0089] In the initial state where no voltage is applied to the piezoelectric element 310, the sensor unit 500 can have a third separation distance d3 between the sensor 520 and the electrode 510 in the optical axis direction. When a voltage is applied to the piezoelectric element 310 to cause the piezoelectric element 310 to extend in a first direction perpendicular to the optical axis, the sensor unit 500 can have a fourth separation distance d4 between the sensor 520 and the electrode 510 in the optical axis direction. The fourth separation distance d4 can be greater than the third separation distance d3.

[0090] Although embodiments of the invention have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that the invention may be implemented in other specific forms without altering its technical spirit or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims

1. A lens driving device, comprising: case; A lens barrel, wherein the lens barrel is disposed in the housing; The lens is disposed in the lens barrel; as well as A driving unit is disposed on the lens barrel. The driving unit includes a piezoelectric element, a first component, and a second component. When a voltage is applied to the piezoelectric element, the piezoelectric element extends or contracts in a direction perpendicular to the optical axis of the lens. The first component is disposed on the piezoelectric element, and the second component is connected to the first component and disposed on the lens barrel. The lens barrel is configured to move along the optical axis of the lens when the voltage is applied to the piezoelectric element. Wherein, the first length in the longitudinal direction of the first component is shorter than the second length in the longitudinal direction of the second component. The housing includes a slit extending straight along a direction parallel to the optical axis. The housing includes an upper plate and side plates extending from the upper plate. The side plates of the housing include a first side plate, a second side plate, a third side plate disposed opposite to the first side plate, and a fourth side plate disposed opposite to the second side plate. The slit is formed on the first side plate of the housing. The lens driving device further includes a third component and a fourth component. The third component is configured to intersect with the first component, and the fourth component is connected to the third component and configured to intersect with the second component. Wherein, each of the first intersection point between the first component and the third component and the second intersection point between the second component and the fourth component is disposed on the slit of the first side plate of the housing, wherein the slit is the passage through which the first intersection point and the second intersection point move in the optical axis direction, and The drive unit is disposed on the first side plate of the housing.

2. The lens driving device according to claim 1, wherein, The first angle formed by the first component and the second component changes when the voltage is applied to the piezoelectric element. The slit is formed as a single slit.

3. The lens driving device according to claim 1, wherein, In the initial state where no voltage is applied to the piezoelectric element, the first angle formed by the first member and the second member is smaller than the second angle formed by the first member and the second member when the voltage is applied to the piezoelectric element.

4. The lens driving device according to claim 1, wherein, The first component and the second component are hinged together.

5. The lens driving device according to claim 1, wherein, The distance the lens barrel moves along the optical axis is determined by the ratio between the first length of the first component and the second length of the second component.

6. The lens driving device according to claim 1, wherein, The distance the lens barrel moves along the optical axis is determined by the number of the second components.

7. The lens driving device according to claim 1, comprising: The first pin is disposed on the lens barrel; as well as A second pin is disposed on the lens barrel and spaced apart from the first pin. The first pin and the second pin are configured to guide the movement of the lens barrel in the optical axis direction.

8. The lens driving device according to claim 1, comprising an electrode and a sensor, the electrode being disposed between the lower portion of the piezoelectric element and the first member, and the sensor being spaced apart from the electrode.

9. The lens driving device according to claim 8, wherein, In the initial state where no voltage is applied to the piezoelectric element, the electrode and the sensor are spaced apart by a first separation distance in the direction perpendicular to the optical axis, and When the voltage is applied to the piezoelectric element, the electrode and the sensor are spaced apart by a second separation distance in a direction perpendicular to the optical axis, and the second separation distance is less than the first separation distance.

10. The lens driving device according to claim 1, wherein, When the voltage is applied to the piezoelectric element, the lens barrel moves away from the piezoelectric element in the direction of the optical axis.

11. The lens driving device according to claim 1, comprising an electrode and a sensor, the electrode being disposed on the first component, and the sensor being disposed on the second component and overlapping the electrode in the optical axis direction.

12. The lens driving device according to claim 11, wherein, In the initial state where no voltage is applied to the piezoelectric element, the electrode and the sensor are spaced apart by a third separation distance along the optical axis, and When the voltage is applied to the piezoelectric element, the electrode and the sensor are spaced apart by a fourth separation distance in the optical axis direction, and the fourth separation distance is smaller than the third separation distance.

13. A lens driving device, comprising: case; A lens barrel, wherein the lens barrel is disposed in the housing; Lens, the lens being connected to the lens barrel; as well as A drive unit configured to move the lens barrel along the optical axis. The driving unit includes a piezoelectric element. The length of the piezoelectric element in the longitudinal direction is configured to change when a voltage is applied to the piezoelectric element. Wherein, the longitudinal direction of the piezoelectric element is perpendicular to the optical axis direction. The driving unit includes a first component and a second component. The first component is connected to the piezoelectric element, and the second component connects the first component and the lens barrel. The housing includes a slit extending straight along a direction parallel to the optical axis. The housing includes an upper plate and side plates extending from the upper plate. The side plates of the housing include a first side plate, a second side plate, a third side plate disposed opposite to the first side plate, and a fourth side plate disposed opposite to the second side plate. The slit is formed on the first side plate of the housing. The lens driving device further includes a third component and a fourth component. The third component is configured to intersect with the first component, and the fourth component is connected to the third component and configured to intersect with the second component. Each of the first intersection point between the first component and the third component, and the second intersection point between the second component and the fourth component, is located on the slit. Wherein, the slit is the path traversed by the first intersection point and the second intersection point as they move along the optical axis direction, and The drive unit is disposed on the first side plate of the housing.

14. The lens driving device according to claim 13, in, The first length in the longitudinal direction of the first component is shorter than the second length in the longitudinal direction of the second component.

15. The lens driving device according to claim 14, wherein, In the initial state where no voltage is applied to the piezoelectric element, the first angle formed by the first member and the second member is smaller than the second angle formed by the first member and the second member when the voltage is applied to the piezoelectric element.

16. The lens driving device according to claim 13, wherein, When the voltage is applied to the piezoelectric element, the lens barrel moves away from the piezoelectric element in the direction of the optical axis.

17. A lens driving device, comprising: case; A lens barrel, wherein the lens barrel is disposed in the housing; Lens, the lens being connected to the lens barrel; as well as A drive unit configured to move the lens barrel along the optical axis. The driving unit includes a piezoelectric element. The length of the piezoelectric element is configured to change when a voltage is applied to it. When the voltage is applied to the piezoelectric element, the distance between the lens barrel and the piezoelectric element increases in the optical axis direction. The driving unit includes a first component and a second component. The first component is disposed on the piezoelectric element, and the second component is connected to the first component and disposed on the lens barrel. The housing includes a slit extending straight along a direction parallel to the optical axis. The housing includes an upper plate and side plates extending from the upper plate. The side plates of the housing include a first side plate, a second side plate, a third side plate disposed opposite to the first side plate, and a fourth side plate disposed opposite to the second side plate. The slit is formed on the first side plate of the housing. The lens driving device further includes a third component and a fourth component. The third component is configured to intersect with the first component, and the fourth component is connected to the third component and configured to intersect with the second component. Each of the first intersection point between the first component and the third component and the second intersection point between the second component and the fourth component is disposed on the slit of the first side plate of the housing. Wherein, the slit is the path traversed by the first intersection point and the second intersection point as they move along the optical axis direction, and The drive unit is disposed on the first side plate of the housing.

18. A camera module comprising a lens driving device according to any one of claims 1 to 17.

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