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US-12619128-B2 - Camera actuator and camera module including same

US12619128B2US 12619128 B2US12619128 B2US 12619128B2US-12619128-B2

Abstract

A lens driving device according to an embodiment includes a moving part including a lens; a driving part for driving the moving part in an optical axis direction; and a sensing part for sensing a position of the moving part; wherein the moving part includes: a magnet scaler in which a first pole and a second pole are alternately arranged in a first direction; and a reference magnet corresponding to the magnet scaler and having a first pole and a second pole disposed in a second direction perpendicular to the first direction.

Inventors

  • Kyung Won Kim

Assignees

  • LG INNOTEK CO., LTD.

Dates

Publication Date
20260505
Application Date
20210420
Priority Date
20200420

Claims (10)

  1. 1 . A lens driving device, comprising: a housing; a fixed part disposed in the housing and including a first lens part; a moving part moving relative to the fixed part and including a lens; a driving part for driving the moving part in an optical axis direction; and a sensing part for sensing a position of the moving part; wherein the moving part includes: a magnet part including: a magnet scaler having a structure in which a plurality of magnets having different polarities are sequentially disposed in the optical axis direction; and a reference magnet including a single-pole magnet in which a N-pole and a S-pole are disposed in a direction perpendicular to the optical axis direction, and wherein the sensing part acquires each of a first sensing signal corresponding to a magnetic force of the reference magnet that changes according to a movement of the moving part and a second sensing signal corresponding to a magnetic force of the magnet scaler that changes according to the movement of the moving part, wherein the magnet scaler and the reference magnet move together with the lens, wherein the driving part moves the moving part to an initial position using the first sensing signal, and moves the moving part to a target position using the second sensing signal, wherein the first sensing signal has a maximum voltage value when the moving part moves to the initial position, wherein the housing includes a hole in which at least a portion of the sensing part is disposed, wherein the magnet part and the sensing part overlaps to each other in the direction perpendicular to the optical axis direction, wherein the moving part further includes: a first lens barrel disposed to be spaced apart from the fixed part in the optical axis direction in the housing; and a second lens barrel disposed to be spaced apart from the moving part in the optical axis direction in the housing, wherein the driving part includes: a first driving part coupled to the first lens barrel in the housing and driving the first lens barrel in the optical axis direction; and a second driving part coupled to the second lens barrel in the housing and driving the second lens barrel in the optical axis direction; wherein the magnet part further includes: a first magnet part including a first magnet scaler and a first reference magnet disposed on one surface of the first lens barrel; and a second magnet part including a second magnet scaler and a second reference magnet disposed on an other surface of the second lens barrel, wherein the sensing part includes: a first sensing part disposed adjacent to the first magnet part; and a second sensing part disposed adjacent to the second magnet part, wherein the first lens barrel includes: a first barrel part including a second lens part; a first guide part extending outwardly from the first barrel part; and a first elastic part connected to the first driving part, wherein the second lens barrel includes: a second barrel part including a third lens part; a second guide part extending outwardly from the second barrel part; and a second elastic part connected to the second driving part, wherein the first driving part includes: a first piezoelectric device disposed in the housing; and a first extension bar extending in the optical axis direction from the first piezoelectric device, wherein the second driving part includes: a second piezoelectric device disposed in the housing; and a second extension bar extending in the optical axis direction from the second piezoelectric device, wherein one region of the first extension bar is connected to the first elastic part, and wherein one region of the second extension bar is connected to the second elastic part.
  2. 2 . The lens driving device of claim 1 , wherein a first pole of the reference magnet is disposed to face at least one of a first pole and a second pole of the magnet scaler.
  3. 3 . The lens driving device of claim 1 , wherein the magnet scaler and the reference magnet are coupled to each other.
  4. 4 . The lens driving device of claim 1 , wherein the driving part moves the moving part to acquire the first sensing signal corresponding to a first reference value at the initial position, and moves the moving part to acquire the second sensing signal corresponding to a second reference value at the target position.
  5. 5 . The lens driving device of claim 1 , wherein the hole includes: a first sub hole corresponding to the magnet scaler, and a second sub hole corresponding to the reference magnet, and wherein the sensing part includes: a first sub sensing part disposed to face the magnet scaler with respect to the first sub hole; and a second sub sensing part disposed to face the reference magnet with respect to the second sub hole.
  6. 6 . The lens driving device of claim 1 , further comprising a substrate disposed on an outer peripheral surface of the housing, wherein at least a portion of the sensing part is positioned in the hole in a state in which the sensing part is disposed on the substrate.
  7. 7 . The lens driving device of claim 1 , wherein the housing includes: a first housing in which the fixed part is disposed; and a second housing in which the first lens barrel and the second lens barrel are disposed, and wherein the hole includes: a first hole formed on a lower surface of the second housing and vertically overlapping with the first magnet part and the first sensing part; and a second hole disposed on an upper surface of the second housing and vertically overlapping with the second magnet part and the second sensing part.
  8. 8 . The lens driving device of claim 1 , further comprising first and second pins extending in the optical axis direction within the housing and spaced apart from each other, wherein the first pin is disposed to be inserted into a first insertion hole of the first lens barrel, wherein the second pin is disposed to be inserted into a second insertion hole of the second lens barrel, wherein the first lens barrel moves along the first pin, and wherein the second lens barrel moves along the second pin.
  9. 9 . The lens driving device of claim 8 , wherein the first lens barrel further includes a first guide groove in which the second pin is disposed, wherein the second lens barrel further includes a second guide groove in which the first pin is disposed, and wherein each of the first and second guide grooves has an open shape at one side.
  10. 10 . The lens driving device of claim 1 , wherein the first magnet part is a first single magnetized magnet in which the first magnet scaler and the first reference magnet are integrally formed, and wherein the second magnet part is a second single magnetized magnet in which the second magnet scaler and the second reference magnet are integrally formed.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is the National Phase of PCT International Application No. PCT/KR2021/004930, filed on Apr. 20, 2021, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2020-0047493, filed in the Republic of Korea on Apr. 20, 2020, all of which are hereby expressly incorporated by reference into the present application. TECHNICAL FIELD An embodiment relates to a camera actuator and a camera module. BACKGROUND ART A camera module captures a subject and stores it as an image or video, and is installed in various devices such as mobile terminals such as cell phones, laptops, drones, and vehicles. In general, the device described above is equipped with a miniature camera module, and the camera module can perform an autofocus (AF) function of automatically adjusting the distance between the image sensor and the lens to align the focal lengths of the lenses. In addition, the camera module may perform a zooming function of zooming up or zooming out by increasing or decreasing the magnification of a distant subject through a zoom lens. In addition, recent camera modules employ image stabilization (IS) technology to correct or prevent image stabilization due to camera movement caused by an unstable fixing device or a user's movement. Such image stabilization (IS) technology includes an optical image stabilizer (OIS) technology and an image stabilization prevention technology using an image sensor. Here, OIS technology is a technology that corrects motion by changing the path of light, and the image stabilization prevention technology using the image sensor is a technology that compensates for motion in both mechanical and electronic ways, and recently, OIS technology is being adopted more and more. Meanwhile, a zoom actuator is used for a zooming function in the camera module. Such an actuator moves the positions of a plurality of zoom lens groups for auto-focusing and change of zoom magnification. At this time, the actuator must accurately sense the current positions of the plurality of zoom lens groups in order to move the positions of the plurality of zoom lens groups, and accordingly move the plurality of zoom lens groups to the target positions. Accordingly, the conventional camera module includes a sensing part for sensing the position of the zoom lens group. For example, the sensing part may include a Hall sensor and a single-pole magnet. At this time, the camera module needs a stroke of 5 to 10 mm or more to realize a high magnification zoom. However, there is a limit to sensing the position of a zoom lens group having a stroke of 5 to 10 mm or more using only the Hall sensor and the single pole magnet. As another example, the sensing part may include a photo interrupter (PI) sensor. However, when the position of the lens group is sensed using the PI sensor, light generated from the PI sensor may enter the image sensor, but there is a problem in that image quality deterioration such as flare occurs. In addition, the PI sensor as described above is difficult to miniaturize, and accordingly, there is a limit in application to a camera module mounted on a terminal. In addition, in the conventional camera module, an initial position of the lens group is measured using a mechanical stopper. However, there is a problem in that the accuracy of the initial position measurement of the lens group using the mechanical stopper decreases due to injection conditions and assembly deviations of various components included in the camera module. Therefore, a new camera module capable of solving the above problems is required. DISCLOSURE Technical Problem An embodiment provides a camera actuator and a camera module having improved optical properties. In addition, the embodiment provides a camera actuator and a camera module capable of autofocus and high magnification zoom. In addition, the embodiment provides a camera actuator and a camera module capable of accurately sensing a current position of a lens group. In addition, the embodiment provides a camera actuator and a camera module that can precisely move the lens group to an initial position. In addition, the embodiment provides a camera actuator and a camera module capable of preventing problems such as de-centering, tilting, friction, etc. occurring when a lens group is moved. In addition, the embodiment provides a camera actuator and a camera module that can have improved process efficiency. Technical problems to be solved by the proposed embodiments are not limited to the above-mentioned technical problems, and other technical problems not mentioned may be clearly understood by those skilled in the art to which the embodiments proposed from the following descriptions belong. Technical Solution A lens driving device according to an embodiment includes a moving part including a lens; a driving part for driving the moving part in an optical axis direction; and a sensing part for sensing a position of the movi