Patent Publication Number: US-2023152551-A1

Title: Optical element driving device, camera device, and electronic apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Chinese Patent Application No. 202111354743.5 filed Nov. 16, 2021, which is hereby incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to an optical element driving device, a camera device and an electronic apparatus used in electronic apparatus such as smartphones. 
     BACKGROUND 
     Some camera devices used in electronic apparatus such as smartphones use a liquid lens unit or the like as an optical element to control the direction of travel of light from a subject. For example, in the imaging system disclosed in Japanese Patent Application Laid-Open No. 2021-505951 (Patent Document 1), an optical element filled with liquid in a container having a transparent bottom portion and a transparent window opposite to the transparent bottom portion is used. In this imaging system, the optical element is deformed by tilting the transparent window around the first axis and tilting the transparent window around the second axis orthogonal to the first axis to control the traveling direction of light passing through the optical element. 
     SUMMARY 
     However, in the technique of Patent Document 1, the transparent window is tilted around the first axis by applying different forces from each other to both ends of the transparent window in the second axis direction of the transparent window, and the transparent window is tilted around the second axis by applying different forces from each other to both ends in the first axis direction of the transparent window. Hereby, the position of the first axis is shifted due to the balance of the forces applied to both ends of the transparent window in the second axis direction of the transparent window and the position of the second axis is shifted due to the balance of the forces applied to both ends of the transparent window in the first axis direction of the transparent window, and as a consequence, there was a problem that the accuracy of controlling the traveling direction of the passing light is deteriorated. In addition, the imaging system disclosed in Patent Document  1  require a complex control system for controlling the forces applied to both ends of the transparent window in the second axis direction of the transparent window and forces applied to both ends of the transparent window in the first axis direction, and as a consequence, there was a problem that it lacks reliability. 
     The present disclosure has been made in view of such problems, and the present disclosure aims to provide an optical element driving device, a camera device and an electronic apparatus. The optical element driving device, a camera device and an electronic apparatus can control with high accuracy in the traveling direction of the passing light of the optical element without performing complex control. 
     To achieve the above-described object, in accordance with a first aspect of the present disclosure, there is provided an optical element driving device including: a fixed portion; an optical element in which liquid is encapsulated between a first end surface and a second end surface opposite to each other and the first end surface is fixed to the fixed portion; a first movable portion supported by the fixed portion and rotatable around an axis of a first rotation shaft; and a second movable portion supported by the first movable portion, rotatable around an axis of a second rotation shaft orthogonal to the first rotation shaft, and fixing the second end surface. 
     In accordance with a second aspect of the present disclosure, there is provided a camera device including the optical element driving device described above. 
     In accordance with a third aspect of the present disclosure, there is provided an electronic apparatus including the camera device described above. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BREIF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view of a smartphone  9  which is an electronic apparatus on which a camera device  8  including an optical element driving device  3  of one embodiment of the present disclosure is mounted. 
         FIG.  2    is a perspective view of the optical element driving device  3  shown in  FIG.  1   ; 
         FIG.  3    is an exploded perspective view of the optical element driving device  3  shown in  FIG.  2   ; and 
         FIG.  4    is a perspective view of the optical element driving device  3  shown in FIG. 2  as viewed from another angle. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Hereinafter, embodiments of the present disclosure are explained with reference to drawings. 
     As shown in  FIG.  1   , in the present embodiment, a camera device  8  is mounted on, for example, an electronic apparatus such as a smartphone  9 . The camera device  8  includes: a prism  2  that bends incident light from a subject at a right angle; an optical element driving device  3  that supports a liquid lens unit  50  passing the passing light of the prism  2  and drives to change the inclination of the incident surface of the light; a lens body  6  that passes the passing light of the liquid lens unit  50 ; and an image sensor  7  that photoelectrically converts the passing light of the lens body  6 . 
     In the following, as shown in  FIG.  2    to  FIG.  4   , a rectangular coordinate system consisting of an X axis, a Y axis and a Z axis orthogonal to each other is assumed, and the configuration of the present embodiment is explained. The Z axis is an axis passing through an optical axis of a lens body  6 . Light from the subject is incident on the prism  2  from the X axis direction, is bent at a right angle by the prism  2 , advances in the Z axis direction and passes through the liquid lens unit  50  and lens body  6 . Hereinafter, in the Z axis direction, a side where the prism  2  is located when viewed from the lens body  6  is referred to as a −Z side, and a side where the image sensor  7  on the opposite side is located is referred to as a +Z side. In addition, in the X axis direction, a side of the subject when viewed from the prism  2  is referred to as a +X side, and its opposite side is referred to as a −X side. 
     As shown in  FIG.  2    to  FIG.  4   , the optical element driving device  3  has an approximate configuration as follows. The optical element driving device  3  includes a fixed portion comprising a case  10 , a liquid lens unit  50  as an optical element, a first movable portion  30 , and a second movable portion  40 . In the liquid lens unit  50 , liquid is encapsulated between a first end surface (a first glass  520 ) and a second end surface (a second glass  540 ) opposite to each other, and the first end surface is fixed to the fixed portion. The first movable portion  30  is supported by the fixed portion so as to be rotatable around the axis of the first rotation shaft  101 . The second movable portion  40  is supported by the first movable portion  30  so as to be rotatable around the axis of the second rotation shaft  102 , and further fixes the second end surface of the liquid lens unit  50 . 
     Further, as shown in  FIG.  3   , the optical element driving device  3  has a first driving portion  15  and a second driving portion  16 , a first detecting portion  17  and a second detecting portion  18 , and a first wire spring  171  and a second wire spring  172 . The first wire spring  171  returns the first movable portion  30  to its point of origin and the second wire spring  172  returns the second movable portion  40  to its point of origin. 
     Before explaining the configuration of the optical element driving device  3 , the prism  2  and a mount portion  20  are explained. The mount portion  20  is a member that supports the prism  2 . As shown in  FIG.  3   , the prism  2  has a cross-sectional shape of a right-angled isosceles triangle surrounded by an incidence surface  2   x  and an emission surface  2   z  orthogonal to each other and a reflection surface  2   t  connecting the incidence surface  2   x  and the emission surface  2   z.  The mount portion  20  has a placing portion  21  with an inclined portion and two side wall portions, and supports the reflection surface  2   t  of the prism  2  by the placing portion  21 . The mount portion  20  supporting the prism  2  is accommodated in the case  10  of the optical element driving device  3  and is fixed to the main body portion of the camera device  8 . Light from the subject is incident from the +X side on the incidence surface  2   x  of the prism  2  supported by the mount portion  20 . This light is bent at a right angle by the reflection surface  2   t  of the prism  2  and is emitted from the emission surface  2   z  to the +Z side. The emitted light from the prism  2  passes through a liquid lens unit  50  and a through hole  14  of the case  10  to be described later and is directed to the lens body  6  and image sensor  7  shown in  FIG.  1   . 
     Next, the configuration of the optical element driving device  3  is explained in detail. In the optical element driving device  3 , the case  10 , which is a fixed portion, is formed by bending a plate-like member, and has a main body portion  13  and two approximately rectangular side plate portions  11  and  12  extending in the −Z axis direction from both ends in the Y axis direction of the main body portion  13 . The through hole  14  is provided in the center of the main body portion  13 . Both sides in the Y axis direction adjacent to the through hole  14  are notched and bent to the −Z axis side to form upright portions, and the respective upright portions are provided with through holes as bearings  111   a,    111   b.  The bearings  111   a  and  111   b  are aligned across the through hole  14  in the Y axis direction. Further, at an edge on the +X side of the main body portion  13 , a portion of the +Y side portion thereof is bent to the −Z axis direction to form an upright portion, and the upright portion is provided with a wire support portion  161 . The optical element driving device  3  is fixed to the main body portion of the camera device  8  by the side plate portions  11  and  12  of the case  10 . In the present embodiment, a portion which is substantially fixed to the main body portion of the camera device  8  and does not move is treated as a fixed portion. 
     As shown in  FIG.  3   , the first movable portion  30 , the second movable portion  40  and the liquid lens unit  50  are arranged between the mount portion  20  and the main body portion  13  of the case  10 . 
     The first movable portion  30  is formed by bending a plate-like member and has a flat plate portion  31 . This flat plate portion  31  has a main body portion  31   a  provided with a through hole  34  that passes emitted light from the emission surface  2   z  of the prism  2 , and an extension portion  31   b  extending from the +X side portion of an edge on the −Y side of the main body portion  31   a  to the −Y axis direction. A side plate portion  32  extends in the −Z axis direction from an edge on the +Y side of the main body portion  31   a.  A first magnet  201  is fixed to the surface on the +Y side of the side plate portion  32 . The first magnet  201  is magnetized in the Y axis direction and the magnetization directions of the +X side portion and the −X side portion are opposite. Further, a side plate portion  33  extends in the −Z axis direction from an edge on the −X side of the extension portion  31   b.  A second magnet  202  is fixed to the surface on the −X side of the side plate portion  33 . The second magnet  202  is magnetized in the X axis direction and the magnetization directions of the +Z side portion and the −Z side portion are opposite. 
     The main body portion  31   a  of the first movable portion  30  has an upright portion protruding in the +Z axis direction and formed with first rotation shafts  101   a  and  101   b  constituting the first rotating shaft  101 . The upright portion formed with the first rotation shaft  101   a  is formed by bending a portion of an edge of the main body portion  31   a  on the −Y side to the +Z side. The first rotation shaft  101   a  is formed as a cylinder protruding from the surface on the −Y side of the upright portion. The upright portion formed with the first rotation shaft  101   b  is formed by notching and bending the main body portion  31   a  to the +Z side. The first rotation shaft  101   b  is formed as a cylinder protruding from the surface on the +Y side of the upright portion. The first rotation shafts  101   a  and  101   b  and the bearings  111   a  and  111   b  in the main body portion  13  of the case  10  are aligned across the through hole  34  in the Y axis direction. The first rotation shafts  101   a  and  101   b  are inserted into the bearings  111   a  and  111   b  of the case  10  and rotatably supported. Therefore, the first movable portion  30  is rotatable around the axes of the first rotation shafts  101   a  and  101   b  parallel to the Y axis direction with respect to the case  10  which is the fixed portion. The axis of rotation formed by the first rotation shaft  101   a  and the first rotation shaft  101   b  is the axis of the first rotation shaft  101 . 
     In the main body portion  31   a  of the first movable portion  30 , an upright portion provided with a wire support portion  151  is formed by bending in the vicinity of the +Y side end portion of the edge on the −X side. Further, in the extension portion  31   b  of the first movable portion  30 , an upright portion provided with a wire support portion  152  is formed by bending at the edge on the −X side. The first wire spring  171  is supported at one end by the wire support portion  151  of the first movable portion  30 , and is supported at the other end by the wire support portion  161  of the case  10 . The first wire spring  171  generates drag force against the rotation driving force around the axis of the first rotation shaft  101  generated in the first movable portion  30 . 
     The second movable portion  40  is formed by bending a plate-like member and has a flat plate portion  41 . The flat plate portion  41  has a main body portion  41   a  provided with a through hole  44  that passes emitted light from the emission surface  2   z  of the prism  2 , and an extension portion  41   b  extending from an edge on the −Y side of the main body portion  41   a . A side plate portion  43  extends in the −Z axis direction from an edge on the +X side of the extension portion  41   b.    
     Upright portions formed with through holes as bearings  112   a  and  112   b  are bent and protrude in the +Z axis direction from edges on the ±X sides of the main body portion  41   a  of the second movable portion  40 . The bearings  112   a  and  112   b  are aligned across the through hole  44  in the X axis direction. Further, the second rotation shafts  102   a  and  102   b  constituting the second rotating shaft  102  of the first movable portion  30  are also aligned across the through hole  34  in the X axis direction. The second movable portion  40  is arranged on the +Z side of the first movable portion  30  with the side plate portion  43  adjacent to the −X side portion of the side plate portion  33 . The second rotation shafts  102   a  and  102   b  of the first movable portion  30  are inserted into the bearings  112   a  and  112   b  of the second movable portion  40  and rotatably supported. Therefore, the second movable portion  40  is rotatable around the axes of the second rotation shafts  102   a  and  102   b  of the first movable portion  30  parallel to the X axis direction with respect to the first movable portion  30 . The axis of rotation formed by the second rotation shaft  102   a  and  102   b  is the axis of the second rotation shaft  102 . 
     Further, in the extension portion  41   b  of the second movable portion  40 , an upright portion provided with a wire support portion  162  is formed by bending at the edge on the −X side. The second wire spring  172  is supported at one end by the wire support portion  152  of the first movable portion  30 , and is supported at the other end by the wire support portion  162  of the second movable portion  40 . The second wire spring  172  generates drag force against the rotation driving force around the axis of the second rotation shaft  102  generated in the second movable portion  40 . 
     Thus, in the present embodiment, the fixed portion comprising the case  10 , the first movable portion  30 , and the second movable portion  40  supported by the first movable portion  30  constitute a gimbal mechanism rotating the first movable portion  30  around the axis of the first rotation shaft ( 101 ) parallel to the Y axis direction and rotating the second movable portion  40  around the axis of the second rotation shaft ( 102 ) parallel to the X axis direction. 
     The liquid lens unit  50  is an optical element formed by arranging a first plate  510 , a first glass  520 , a liquid lens  530 , a second glass  540  and a second plate  550  in the −Z axis direction. The first plate  510  and the second plate  550  are provided with through holes  511  and  551  that pass the emitted light from the emission surface  2   z  of the prism  2 , respectively. Further, notch portions  512   a  and  512   b  are provided at the edges on both sides in the Y axis direction of the first plate  510  to pass through the upright portions provided with the bearings  111   a  and  111   b  of the case  10 . The upright portions provided with the bearings  111   a  and  111   b  reach the positions of the upright portions provided with the first rotation shafts  101   a  and  101   b  of the first movable portion  30  via the notch portions  512   a  and  512   b.    
     The liquid lens  530  is formed by filling a transparent flexible container with liquid. The first plate  510  is fixed to the surface on the −Z side of the main body portion  13  of the case  10 . The second plate  550  is fixed to the surface on the +Z side of the main body portion  41   a  of the second movable portion  40 . The first glass  520  is fixed to the first plate  510  and the liquid lens  530  and maintains the flatness the surface of the liquid lens  530  on the +Z side. The second glass  540  is fixed to the second plate  550  and the liquid lens  530  and maintains the flatness of the surface of the liquid lens  530  on the −Z side. Further, stoppers  552  protruding to the +Z side are provided at four corners of the second plate  550 . Therefore, when the second movable portion  40  is inclined around the axis of the first rotation shaft  101  and/or around the axis of the second rotation shaft  102 , the second plate  550  is also inclined according to the inclination of the second movable portion  40 , and according to the inclination of the second plate  550 , the surface on the −Z side of the liquid lens  530  is inclined while remaining flat. In the liquid lens unit  50  according to the present embodiment, the first glass  520  serves as a first end surface supported by the fixed portion and the second glass  540  serves as a second end surface supported by the second movable portion  40 . Thereby, the emitted light of the prism  2  advances in a direction inclined to the optical axis of the lens body  6 , so that the position of incidence on the image sensor  7  is changed. Conversely, when the direction of the light incident on the camera device  8  is changed due to hand shake or the like, the position of incidence on the image sensor  7  can be maintained constant. 
     It is desirable that the centers of the through holes  14 ,  34 ,  44 ,  511 , and  551  coincide when viewed from the Z axis direction, and the center of the through hole  511  is the center of the first end surface, i.e. the center of the first glass  520 , and the first end surface is orthogonal to the Z axis. In addition, when viewed form the Z axis direction, it is desirable that the first rotation shaft  101  and the second rotation shaft  102  pass through the center of the through hole  511 . In addition, when viewed from a direction orthogonal to the Z axis, it is desirable that the first rotation shaft  101  and the second rotation shaft  102  overlap with the second end surface, i.e. the center of the second glass  540 , that is, are at the same height. In addition, when viewed form the Z axis direction, when the first wire spring  171  is support on the axis line of the first rotation shaft  101  of the first movable portion  30 , there is no change in height, so that the wire support portion  151  is provided at a place that is not on the axis line of the first rotation shaft  101 . Similarly, when viewed from the Z axis direction, when the second wire spring  172  is supported on the axis line of the second rotation shaft  102  of the second movable portion  40 , there is no changed in height, so that the wire support portion  162  is provided at a place that is not on the axis line of the second rotation shaft  102 . 
     As shown in  FIG.  3   , the FPC (Flexible Printed Circuit board)  60  has a strip-like portion  61  extending in the Y axis direction and a side surface portion  62  bent and projecting in the +Z axis direction from the −Y side end portion of the strip-like portion  61 . A +Y side end portion of the strip-like portion  61  is bent and projects in the −Z axis direction, and is further folded back to the −Y axis direction, and a side surface portion  63  is provided at the end portion. A first coil  301  long in the Z axis direction is disposed on the surface on the −Y side of the side surface portion  63 . An electric current flows in the first coil  301  via the strip-like portion  61 . Further, a Hall element  311 , which is the first magnetic sensor, is disposed inside the winding of the first coil  301  on the surface of the −Y side of the side surface portion  63 . In the FPC  60 , the side surface portion  63  is fixed on the −Y side (inside) portion of the side plate portion  12  of the case  10 , and the strip-like portion  61  is fixed along the edge on the −X side of the outside of the side plate portion  12  and main body portion  13 . The first coil  301  and the Hall element  311  disposed at the side surface portion  63  of the FPC  60  are opposed to the first magnet  201  disposed at the side plate portion  32  of the first movable portion  30 . The first magnet  201  and the first coil  301  constitute the first driving portion  15  rotationally driving the first movable portion  30  around the axis of the first rotation shaft  101  with respect to the case  10  which is the fixed portion. Further, the first magnet  201  and the Hall element  311  which is the first magnetic sensor constitute the first detecting portion  17  detecting the rotation displacement of the first movable portion  30  around the axis of the first rotation shaft  101 . The side surface portion  62  is electrically connected to the main body of the camera device  8 . 
     As shown in  FIG.  3   , the FPC (Flexible Printed Circuit board)  70  has a side surface portion  71  orthogonal to the X axis direction, a side surface portion  72  fixed to the side surface portion  62  of the FPC  60 , and a strip-like portion  73  connecting the side surface portion  71  and the side surface portion  72 . A second coil  302  long in the Y axis direction is disposed on the surface on the +X side of the side surface portion  71 . An electric current flows in the second coil  302  via the strip-like portion  73 . Further, a Hall element  312 , which is the second magnetic sensor, is disposed inside the winding of the second coil  302  on the surface on the +X side of the side surface portion  71 . In the FPC  70 , the side surface portion  71  is fixed to the surface on the +X side of the side plate portion  43  of the second movable portion  40 . The second coil  302  and Hall element  312  disposed at the side surface portion  71  of the FPC  70  are opposed to the second magnet  202  disposed on the surface on the −X side of the side plate portion  33  of the first movable portion  30 . The second magnet  202  and the second coil  302  constitute the second driving portion  16  rotationally driving the second movable portion  40  around the axis of the second rotation shaft  102  with respect to the first movable portion  30 . 
     Further, the second magnet  202  and the Hall element  312  which is the second magnetic sensor constitute the second detecting portion  18  detecting the rotation displacement of the second movable portion  40  around the axis of the second rotation shaft  102 . 
     As shown in  FIG.  4   , the strip-like portion  73  first extends from the side surface portion  72  in the −Z axis direction, thereafter is curved to change the orientation to the +Y axis direction, and end portion of the strip-like portion  73  enters inside the case  10  from the outside. Then, a portion of the strip-like portion  73  which enters inside the case  10  and opposes to the −X axis side portion of the side plate portion  43  extends in the +Y axis direction, thereafter, bends and extends in the +Z axis direction, then an end portion in the direction of travel bends and extends in the −Y axis direction, bends and extends in the −Z axis direction, then bends and extends in the +Y axis direction. 
     Finally, an end portion in the direction of travel is changed in orientation to the +X axis direction, reaches the +X axis side portion of the side plate portion  43 , and is connected to the side surface portion  71 . Thus, the strip-like portion  73  is provided in a swirl shape, and thereby, the second movable portion  40  can rotate without being affected by the tension of the FPC  70 . 
     In the present embodiment, when inclining the second glass  540  which is the second end surface of the liquid lens unit  50  which is the optical element around the axis of the first rotation shaft  101  and/or around the axis of the second rotation shaft  102 , a predetermined electric current is applied to the first coil  301  and/or the second coil  302 . The predetermined electric current is an electric current having a polarity corresponding to a desired inclination direction around the axis of the first rotation shaft  101  and a magnitude corresponding to a desired inclination angle, and/or an electric current having a polarity corresponding to a desired inclination direction around the axis of the second rotation shaft  102  and a magnitude corresponding a desired inclination angle. The electric current is supplied to the first coil  301  via the FPC  60  and is supplied to the second coil  302  via the FPC  70 . As a result, the first movable portion  30  is driven by the electromagnetic force in the X axis direction acting between the first magnet  201  and the first coil  301 , and rotates around the axis of the first rotation shaft  101 . Further, the second movable portion  40  is driven by the electromagnetic force in the Z axis direction acting between the second magnet  202  and the second coil  302 , and rotates around the axis of the second rotation shaft  102 . Thereby, the second movable portion  40  is inclined with respect to the case  10  which is the fixed portion, and the second glass  540  which is the second end surface of the liquid lens unit  50  is inclined according to the inclination of the second movable portion  40 . The Hall element  311  detects the rotation displacement of the first movable portion  30  around the axis of the first rotation shaft  101  based on the magnetic field received from the first magnet  201 , and the Hall element  312  detects the rotation displacement of the second movable portion  40  around the axis of the second rotation shaft  102  based on the magnetic field received from the second magnet  202 . The electric current flowing in the first coil  301  and/or the second coil  302  is adjusted based on the detected value of the rotation displacement. 
     The above are the details of the configuration of the embodiment of the present disclosure. The optical element driving device  3  according to the present embodiment includes: a case  10  which is a fixed portion; a liquid lens unit  50  which is an optical element in which liquid is encapsulated between a first end surface and a second end surface opposite to each other and the first end surface is fixed to the case  10 ; a first movable portion  30  supported by the case  10  and rotatable around an axis of the first rotation shaft  101 ; and a second movable portion  40  supported by the first movable portion  30 , rotatable around an axis of a second rotation shaft  102  orthogonal to the first rotation shaft  101 , and fixing the second end surface. Therefore, since the positions of the first rotation shaft  101  and the second rotation shaft  102  do not shift, even if complicated control is no performed, the accuracy of controlling the inclination around the axis of the first rotation shaft  101  and the inclination around the axis of the second rotation shaft  102  for the second end surface of the liquid lens unit  50  can be improved. That is, the accuracy of controlling the traveling direction of transmitted light of the liquid lens unit  50  is high. 
     It is to be noted that, the first driving portion  15  only needs to be arranged so that the driving force acts in the tangential direction of the circle centered on the first rotation shaft  101 . Further, the second driving portion  16  only needs to be arranged so that the driving force acts in the tangential direction of the circle centered on the second rotation shaft  102 . 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.