Patent Publication Number: US-2019196138-A1

Title: Camera module

Description:
TECHNICAL FIELD 
     The present invention relates to a camera module. 
     BACKGROUND ART 
     A recent information processing terminal such as a smartphone and a tablet terminal is equipped with a compact camera module for taking an image. Such a camera module includes a lens drive unit that has an autofocus function to automatically focus at the time of taking an image of an object and a stabilizer function to optically compensate for camera shake occurring at the time of taking an image to reduce blur of the image. 
     The autofocus function of the lens drive unit is realized by a voice coil motor that includes a magnet and a coil as shown in Patent Document 1, for example. Use of drive force of the voice coil motor reciprocates a lens to along an optical axis direction. With this, the lens drive unit supports reciprocation of the lens along the optical axis direction by the autofocus function with the use of a guide ball placed around. 
     Further, the stabilizer function of the lens drive unit includes, for example, a magnet mounted on a housing that houses a lens barrel and a coil installed on a bottom cover. Applying electric current to the coil in such a configuration causes drive force to move the housing that houses the lens barrel in predetermined one direction on a vertical plane to the optical axis direction of the lens. With two voice coil motors each including the magnet and the coil, it is possible to drive the housing to reciprocate in two linear directions (X-axis direction and Y-axis direction) orthogonal to each other on the vertical plane to the optical axis direction of the lens. 
     In recent years, an information processing terminal equipped with two cameras that image in the same directions, namely, a dual camera has appeared. Imaging in the same directions with two cameras allows acquisition of various captured image information and enhancement of an imaging function. 
     Patent Document 1: Japanese Unexamined Patent Application Publication No. JP-A 2015-180937 
     As described above, for mounting a dual camera on an information processing terminal, there is a need to set camera modules close to each other. Then, there is a case where magnets included by stabilizer functions of the camera modules are close to each other, and magnetic interference may thereby occur. Such magnetic interference may cause a problem of trouble and decline of accuracy in the stabilizer function. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to solve the abovementioned problem, namely, a problem of decline of a stabilizer function of a lens drive unit in a dual camera. 
     A camera module as an aspect of the present invention is a camera module equipped with two lens drive units adjacent to each other. 
     The lens drive units each include a first drive mechanism configured to move a lens along an optical axis direction and a second drive mechanism configured to move the lens in a vertical direction to the optical axis direction. 
     The second drive mechanism includes two voice coil motors that respectively move the lens in two linear directions orthogonal to each other on a vertical plane to the optical axis direction of the lens. 
     Each of the lens drive units has a substantially rectangular outline. 
     The two voice coil motors configuring the second drive mechanism are respectively installed near two sides neighboring each other of four sides forming an outer perimeter of the substantially rectangular lens drive unit. 
     The two lens drive units are installed so that none of the voice coil motors are located on at least one of sides where the lens drive units are located adjacent to each other. 
     Moreover, in the camera module, 
     the two lens drive units are installed so that none of the voice coil motors are located on the sides where the lens drive units are located adjacent to each other. 
     Moreover, in the camera module, 
     the two lens drive units are installed so that the voice coil motors are located symmetrical about a symmetric line, the symmetric line being the sides where the lens drive units are located adjacent to each other. 
     Moreover, in the camera module, 
     the two lens drive units are installed so that the voice coil motors are located symmetrical about a symmetric point, the symmetric point being near a center of the sides where the lens drive units are located adjacent to each other. 
     Further, the present invention also provides an information processing terminal equipped with the camera module described above. 
     According to the camera module of the present invention, the voice coil motors for realizing the stabilizer functions of the lens drive units configuring the dual camera are not installed adjacent to each other, magnetic interference can be thereby inhibited. As a result, it is possible to inhibit decline of the stabilizer function of the lens drive unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing a configuration of a camera module in a first exemplary embodiment of the present invention; 
         FIG. 2  is a view showing a configuration and operation of a lens drive unit configuring the camera module disclosed in  FIG. 1 ; 
         FIG. 3  is a view showing an example of arrangement of the lens drive units in the camera module disclosed in  FIG. 1 ; 
         FIG. 4  is a view showing an example of arrangement of the lens drive units in the camera module disclosed in  FIG. 1 ; 
         FIG. 5  is a view showing an example of arrangement of the lens drive units in the camera module disclosed in  FIG. 1 ; 
         FIG. 6  is a view showing a configuration of a camera module according to a second exemplary embodiment of the present invention; and 
         FIG. 7  is a view showing a configuration and operation of a lens drive unit configuring the camera module disclosed in  FIG. 6 . 
     
    
    
     EXEMPLARY EMBODIMENT 
     &lt;First Exemplary Embodiment&gt; 
     A first exemplary embodiment of the present invention will be described with reference to  FIGS. 1 to 5 .  FIGS. 1 and 2  are views showing a configuration of a camera module.  FIGS. 3 to 5  are views showing arrangement of lens drive units configuring the camera module. 
     The camera module according to the present invention is, for example, for taking an image, mounted on an information processing terminal such as a smartphone and a tablet terminal. However, the camera module according to the present invention is not necessarily limited to being mounted on an information processing terminal, and may be mounted on other electronic equipment or various types of equipment. 
     With reference to  FIG. 1 , the configuration of the camera module will be described.  FIG. 1  is a plan view showing the configuration of the camera module in a simplified manner. In the drawings of this application, part of the configuration is omitted for clarity of a structure. 
     The camera module according to the present invention is a dual camera including two cameras. Therefore, the camera module includes two lens drive units  1 A and  1 B. As shown in  FIG. 1 , the lens drive units  1 A and  1 B are installed adjacent to each other. To be specific, the lens drive units  1 A and  1 B are formed so as to have substantially square outlines and are installed so that one sides of four sides forming outer perimeters are parallel to each other and adjacent to the other. The outlines of the lens drive units  1 A and  1 B are not limited to be square and may be rectangular, so that the outlines are formed so as to be substantially rectangular. 
     In this exemplary embodiment, the lens drive units  1 A and  1 B are the same ones. The lens drive units  1 A and  1 B each have an autofocus function to automatically focus at the time of taking an image of an object and a stabilizer function to optically compensate for camera shake occurring at the time of taking an image to reduce blur of the image. Below, configurations of the lens drive unit that realize the autofocus function and the stabilizer function will be mainly described, but the lens drive units may each have a function other than the functions illustrated in this exemplary embodiment. The lens drive units  1 A and  1 B may have different configurations from each other as far as magnets serving as the configuration for realizing the stabilizer function are arranged in a manner described below. 
     The lens drive unit  1 A configuring the camera module includes a cover (not shown in the drawings) that covers the top and a bottom cover (not shown in the drawings) that convers the bottom. In  FIG. 1 , the lens drive unit  1 A is illustrated with the cover and the bottom cover omitted. The lens drive unit  1 A includes a lens barrel  21  equipped with a lens (not shown in the drawings) and a housing  22  that surrounds the lens barrel  21  to house the lens barrel  21 , in a space made by the cover and the bottom cover. In addition, the lens drive unit  1 A includes a first drive mechanism ( 31 ,  32 ,  33 ) that moves the lens barrel along the optical axis direction of the lens with respect to the housing  22 , and a second drive mechanism ( 51 ,  52 ) that moves the housing  22  in a vertical direction to the optical axis direction of the lens with respect to the bottom cover. Below, each configuration will be described in detail. 
     The lens barrel  21  has an outline formed into a substantially rectangular shape. At the center of the lens barrel  21 , a lens housing hole for housing the lens is formed. Moreover, the housing  22  is formed by, for example, four side walls and is a tubular member that has a substantially rectangular end face, and houses the lens barrel  21  inside. 
     The first drive mechanism ( 31 ,  32 ,  33 ) is a configuration that moves the lens barrel  21  along the optical axis direction of the lens, namely, along a vertical direction to the page of  FIG. 1  and thereby realizes the autofocus function. To be specific, the first drive mechanism ( 31 ,  32 ,  33 ) in this exemplary embodiment drives the lens barrel  21  by SIDM (Smooth Impact Drive Mechanism) method, and has a drive shaft  31  serving as a piezoelectric actuator, a spring mechanism  32  and a guide mechanism  33 . 
     The drive shaft  31  is a cylindrical shaft member that is installed on the housing  22  and extends along the thickness direction of the lens barrel  21 , namely, along the optical axis direction of the lens. The drive shaft  31  is installed so that its lateral face contacts a concave part formed at a corner position between two neighboring sides of the rectangular lens barrel  21 . The drive shaft  31  is configured to be stretched and contracted in its length direction by a piezoelectric element that is not shown in the drawings. 
     Further, the spring mechanism  32  is installed on the housing  22  or the bottom cover (not shown in the drawings) and presses the drive shaft  31  against the concave part formed at the corner of the lens barrel  21 . Consequently, the drive shaft  31  and the lens barrel  21  are engaged by friction force and can thereby move the lens barrel  21  in the optical axis direction as the drive shaft  31  stretches and contracts. 
     Further, the guide mechanism  33  is set at a corner position of the lens barrel  21  opposite the corner position where the drive shaft  31  contacts, across the lens barrel  21 . The guide mechanism  33  includes a protruding part that protrudes from the lens barrel  21  and a housing concave part formed on the housing  22  to house the protruding part. The housing concave part is formed like a groove along the optical axis direction. Therefore, when the lens barrel  21  is moved along the optical axis direction of the lens barrel  21  by the drive shaft  31  as described above, the protruding part of the lens barrel  21  is guided by the housing concave part. 
     The second drive mechanism ( 51 ,  52 ) is a configuration that moves the lens barrel  21  in a vertical direction to the optical axis direction of the lens and thereby realizes the stabilizer function. To be specific, the second drive mechanism ( 51 ,  52 ) includes two voice coil motors  51  and  52  and moves the housing  22  that houses the lens barrel  21  with respect to the bottom cover. As shown in  FIG. 1 , the two voice coil motors  51  and  52  are respectively installed near two neighboring sides of four sides forming the outer perimeter of the substantially rectangular lens drive unit  1 A. That is, the two voice coil motors  51  and  52  are respectively installed along and near the two sides orthogonal to each other. 
     One voice coil motor  51  is set near a side located on the upper side in  FIG. 1  and moves the housing  22  in the vertical direction in  FIG. 1 . Moreover, the other voice coil motor  52  is set near a side located on the right side in  FIG. 1  and moves the housing  22  in the horizontal direction in  FIG. 1 . Thus, the two voice coil motors  51  and  52  respectively move the lens in two linear directions orthogonal to each other on a vertical plane to the optical axis direction. 
     To be specific, one of the voice coil motors includes a magnet  51  installed on the lower face of the housing  22  and a coil (not shown in the drawings) set on the bottom cover so as to correspond to the magnet  51 . Likewise, as shown in  FIG. 2 , the other voice coil motor includes a magnet  52  installed on the lower face of the housing  22  and a coil  52   b  set on the bottom cover so as to correspond to the magnet  52 . The one voice coil motor including the magnet denoted by reference numeral  51  shown in  FIG. 1 , when electric current is applied to the coil corresponding to the magnet  51 , moves the lens along one linear direction (Y-axis direction) on the vertical plane to the optical axis direction of the lens. Moreover, the other voice coil motor including the magnet denoted by reference numeral  52 , when electric current is applied to the coil  52   b  corresponding to the magnet  52 , moves the lens along the other linear direction (X-axis direction) orthogonal to the one linear direction on the vertical plane to the optical axis direction of the lens. To be specific, when electric current is applied to the coil  52   b,  due to the direction of the electric current and Fleming&#39;s left-hand rule, the lens barrel is driven to reciprocate along a direction (Z-axis direction) vertical to the optical axis direction of the lens. 
     As shown in  FIG. 1 , the other lens drive unit  1 B included by the camera module has the same configuration as the lens drive unit  1 A described above. 
     Furthermore, in this exemplary embodiment, the abovementioned two lens drive units  1 A and  1 B configuring the dual camera are installed as shown in  FIG. 3 or 4 . First, as shown in the upper view and the lower view of  FIG. 3 , the lens drive units  1 A and  1 B are installed so that the magnets  51  and  52  included by the voice coil motors are located on neither of sides where the lens drive units  1 A and  1 B are located adjacent to each other. 
     To be specific, in the example shown in the upper view of  FIG. 3 , one lens drive unit  1 A located on the left is installed so that the magnets  51  and  52  are located near the left and upper sides of the outer perimeter, and the other lens drive unit  1 B located on the right is installed so that the magnets  51  and  52  are located near the right and lower sides. Thus, the magnets  51  and  52  configuring the stabilizer function of the lens drive unit  1 A and those of the lens drive unit  1 B are installed so as to be located symmetrical about the vicinity of the center of the sides where the lens drive units  1 A and  1 B are located adjacent to each other. Consequently, neither of the magnets  51  and  52  are located at positions where the lens drive units  1 A and  1 B are adjacent to each other, so that magnetic interference can be inhibited. 
     Further, in the example shown in the lower view of  FIG. 3 , one lens drive unit  1 A located on the left is installed so that the magnets  51  and  52  are located near the left and upper sides of the outer perimeter, and the other lens drive unit  1 B located on the right is installed so that the magnets  51  and  52  are located near the upper and right sides. Thus, the magnets  51  and  52  configuring the stabilizer function of the lens drive unit  1 A and those of the lens drive unit  1 B are installed so as to be located symmetric about the sides where the lens drive units  1 A and  1 B are located adjacent to each other. Consequently, neither of the magnets  51  and  52  are not located at positions where the lens drive units  1 A and  1 B are adjacent to each other, so that magnetic interference can be inhibited. 
     Further, in this exemplary embodiment, as shown in the upper view and the lower view of  FIG. 4 , the two lens drive units  1 A and  1 B configuring the dual camera may be installed so that neither of the magnets  51  and  52  included by the voice coil motors are located on one of sides where the lens drive units  1 A and  1 B are located adjacent to each other. 
     To be specific, in the example shown in the upper view of  FIG. 4 , one lens drive unit  1 A located on the left is installed so that the magnets  51  and  52  are located near the left and upper sides of the outer perimeter, and the other lens drive unit  1 B located on the right is installed so that the magnets  51  and  52  are located near the lower and left sides. Thus, even if the magnet  52  of the lens drive unit  1 B is located between the lens drive units  1 A and  1 B, magnetic interference can be inhibited. 
     Further, in the example shown in the lower view of  FIG. 4 , one lens drive unit  1 A located on the left is installed so that the magnets  51  and  52  are located near the left and upper sides of the outer perimeter, and the other lens drive unit  1 B located on the right is installed so that the magnets  51  and  52  are located near the left and upper sides. Thus, even if the magnet  52  of the lens drive unit  1 B is located between the lens drive units  1 A and  1 B, magnetic interference can be inhibited. 
     Examples shown in the upper and lower views of  FIG. 5  are examples for comparison with the configurations of the present invention shown in  FIGS. 3 and 4  described above. In a case where, as shown in the upper view and the lower view of  FIG. 5 , the magnets  51  and  52  configuring the stabilizer functions of the respective lens drive units  1 A and  1 B are located on sides where the lens drive units  1 A and  1 B are located adjacent to each other, magnetic interference may occur due to these magnets  51  and  52 . Therefore, it is desirable to install as shown in  FIG. 3 or 4 . 
     As described above, according to the camera module of the present invention shown in  FIGS. 3 and 4 , the voice coil motors for realizing the stabilizer functions of the respective lens drive units configuring the dual camera are not installed adjacent to each other, so that it is possible to inhibit magnetic interference. As a result, it is possible to inhibit decline of the stabilizer function of the lens drive unit. 
     &lt;Second Exemplary Embodiment&gt; 
     Next, a second exemplary embodiment of the present invention will be described with reference to  FIGS. 6 and 7 . The lens drive units  1 A and  1 B in this exemplary embodiment are different from those in the first exemplary embodiment described above in the configuration of the first drive mechanism that realizes the autofocus function. Meanwhile, the configuration of the second drive unit that realizes the stabilizer function is the same as that in the first exemplary embodiment described above. Below, the different configuration will be described in detail. 
     The lens drive unit  1 A in the second exemplary embodiment of the present invention drives the lens barrel  21  to move along the optical axis direction with the use of an autofocus voice coil motor, which is different from the second drive mechanism described above. To be specific, a first drive mechanism ( 41 - 45 ) includes a pair of guide balls  41  and  42 , and two autofocus voice coil motors ( 43 - 45 ). 
     The one guide ball  41  is installed between a concave part and a first guide ball retaining part; the concave part is formed at a corner position between two neighboring sides of the rectangular lens barrel  21 , and the first guide ball retaining part has a concave shape and is formed on the housing  22 . Moreover, the other guide ball  42  is installed between a second concave part and a second guide ball retaining part; the second concave part is formed at the other corner position of the lens barrel  21  located diagonally opposite the corner position with the one guide ball  41  installed across the lens barrel  21 , and the second guide ball retaining part is set at a corner position of the housing  22  so as to face the other corner position. Consequently, when the lens barrel  21  moves along the optical axis direction with respect to the housing  22 , the guide balls  41  and  42  inserted therebetween roll, and the lens barrel  21  thereby moves smoothly. 
     The two autofocus voice coil motors ( 43 - 45 ) are respectively installed near two sides adjacent to each other of four sides forming the outer perimeter of the substantially rectangular lens drive unit  1 A. That is, the two autofocus voice coil motors ( 43 - 45 ) are respectively installed near two sides orthogonal to each other. Meanwhile, near the remaining two sides orthogonal to each other forming the outer perimeter of the lens drive unit  1 A, voice coil motors  51  and  52  serving as a second drive mechanism. 
     In the example shown of  FIG. 6 , the one autofocus voice coil motor ( 43   a,    44   a,    45   a ) is installed near the left-side lateral face of the lens drive unit  1 A. To be specific, the one autofocus voice coil motor ( 43   a,    44   a,    45   a ) includes the magnet  43   a  installed on the lateral face of the lens barrel  21 , and the coil  44   a  and the yoke  45   a  installed on the lateral face of the housing  22  facing the magnet  43   a.  Moreover, the other autofocus voice coil motor ( 43   b,    44   b,    45   b ) is installed near the lower-side lateral face of the lens drive unit  1 A. To be specific, the other autofocus voice coil motor ( 43   b,    44   b,    45   b ) includes the magnet  43   b  installed on the lateral face of the lens barrel  21 , and the coil  44   b  and the yoke  45   b  installed on the lateral face of the housing  22  facing the magnet  43   b.    
     In the one voice coil motor ( 43   a,    44   a,    45   a ), as shown in  FIG. 7 , magnetic flux from the magnet  43   a  whose upper and lower sides are magnetized with N pole and S pole on a lens barrel  21  side is concentrated to the yoke  45   a.  Then, applying electric current to the coil  44   a  causes drive force to move the lens barrel  21  along the optical axis direction of the lens. To be specific, when electric current is applied to the coil  44   a,  the lens barrel is driven to reciprocate along the optical axis direction of the lens (Z axis direction) according to Fleming&#39;s left hand rule due to the direction of the electric current and the magnetic flux passing the coil  44   a  from the magnet  43   a.  Likewise, when electric current is applied to the coil  44   b,  the other voice coil motor ( 43   b,    44   b,    45   b ) is also driven to reciprocate along the optical axis direction of the lens (Z axis direction) according to Fleming&#39;s left hand rule due to the direction of the electric current and the magnetic flux passing the coil  44   b  from the magnet  43   b.    
     Then, the magnets  43   a  and  43   b  of the autofocus voice coil motors are attracted to the yokes  45   a  and  45   b,  respectively. Therefore, the lens barrel  21  is attracted toward the left side and the lower side, so that the lens barrel  21  is kept pressed against the one guide ball  41  due to resultant force. Moreover, the lens barrel  21  is supported by the other guide ball  42  on the other side on the diagonal. Herein, by making the shape of the yoke  45   b  configuring the other voice coil motor larger than the shape of the yoke  45   a  configuring the one voice coil motor, it is possible to apply clockwise rotational force to the lens barrel  21  because force to attract the magnet  44   b  of the other voice coil motor becomes larger than force to attract the one voice coil motor. Consequently, it is possible to press the lens barrel  21  against the other guide ball  21 . 
     Consequently, the lens barrel  21  is kept in contact with the housing  22  via the pair of guide balls  41  and  42 . Then, movement in a vertical direction to the optical axis in the housing  22  is regulated, so that the posture of the lens barrel  21  becomes stable. As a result, it is possible to realize a stable autofocus operation without instability of the optical axis. 
     Further, the lens drive unit  1 A in this exemplary embodiment includes the voice coil motors  51  and  52  configuring the similar second drive mechanism to that of the first exemplary embodiment, on the different two sides of the outer perimeter from the two sides with the autofocus voice coil motors ( 43 - 45 ) set. 
     Then, as shown in  FIG. 6 , the other lens drive unit  1 B included by the camera module has the same configuration as the one lens drive unit  1 A described above. 
     Also in this exemplary embodiment, the two lens drive units  1 A and  1 B described above included by the dual camera are installed as shown in  FIGS. 3 and 4  in a similar manner as in the first exemplary embodiment. That is, neither of the magnets  51  and  52  included by the voice coil motors configuring the second drive mechanism are located on at least one of sides where the lens drive units  1 A and  1 B are located adjacent to each other. 
     On the sides where the lens drive units  1 A and  1 B are located adjacent to each other, at least one of the magnets  43   a  and  43   b  of the autofocus voice coil motors configuring at least one first drive mechanism is located. For example, in the example of  FIG. 3 , the magnets  43   a  and  43   b  of the two autofocus voice coil motors are located adjacent to each other. In the example of  FIG. 4 , the magnet ( 43   a  or  43   b ) of the one autofocus voice coil motor and the magnet ( 51  or  52 ) of the one voice coil motor configuring the second drive mechanism are adjacent to each other. 
     However, the autofocus voice coil motors configuring the first drive mechanism include the yokes  45   a  and  45   b  outside the magnets  43   a  and  43   b.  Therefore, it is possible to inhibit magnetic interference between the magnets adjacent to each other as described above. 
     As described above, according to the camera module in this exemplary embodiment, magnetic interference of the magnets configuring the lens drive units configuring the dual camera can be inhibited. As a result, it is possible to inhibit of decline of the stabilizer function of the lens drive unit. 
     Although the present invention has been described above with reference to the exemplary embodiments and so on, the present invention is not limited to the exemplary embodiments. The configurations and details of the present invention can be changed in various manners that can be understood by one skilled in the art within the scope of the present invention.