Patent Publication Number: US-2020292775-A1

Title: Imaging device and method of manufacturing imaging device

Description:
TECHNICAL FIELD 
     The present technology relates to an imaging device and a method of manufacturing an imaging device. Specifically, the present technology relates to an imaging device used by being incorporated in a device or the like and a method of manufacturing the imaging device. 
     BACKGROUND ART 
     Conventionally, cameras in which a plurality of imaging elements is arranged have been used. For example, in cameras that generate a three-dimensional (3D) image, a camera that generates two image signals using two imaging elements arranged with a predetermined distance from each another is used. In this case, since an optical system member such as a lens is arranged for each imaging element, optical axes of the plurality of imaging elements need to be adjusted. Therefore, a camera is used, in which one module is configured by combining an imaging element and an optical system member, and the optical axis is adjusted for each module before mounting. For example, a camera is used, in which first and second camera modules each including a lens barrel and an image sensor are mounted on one mechanical member (for example, see Patent Document 1). 
     In the above-described camera, after the first camera module is fixedly coupled to the mechanism member, the first camera module performs imaging and obtains a data value. Next, the second camera module similarly performs imaging and obtains a data value. Optical axis adjustment is performed by comparing these two data values and adjusting the position of the second camera module with reference to the first camera module. Thereafter, the second camera module is fixedly coupled to the mechanism member. Here, coupling members are arranged on a pair of opposed side surfaces of the camera modules. Furthermore, the mechanism member includes a mounting portion extending from a bottom surface to an upper side so as to support the pair of opposed side surfaces of the camera modules. The camera modules are arranged on the bottom surface of the mechanism member, and the coupling members of the camera modules and the mounting portion of the mechanism member are coupled by soldering or the like, so that the first and second camera modules with adjusted optical axes and the mechanism member are coupled. Thereafter, the mechanism member to which the first and second camera modules are fixedly coupled is attached to the camera. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Patent Application Laid-Open No. 2012-173737 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     In the above-described related art, the camera modules and the mechanical member are coupled to each other on the pair of opposed side surfaces, and there is a problem that strength is insufficient. 
     The present technology has been made in view of the above-described problem, and an object of the present technology is to improve strength of an imaging module with an adjusted optical axis. 
     Solutions to Problems 
     The present technology has been made to solve the above-described problem, and the first aspect of the present technology is an imaging device including an imaging module provided with an imaging element configured to image incident light introduced from an upper surface of a housing, and a holding unit configured to surround and hold a side surface of the imaging module, the side surface being adjacent to the upper surface. This brings about an effect that the side surface of the imaging module is surrounded by the holding unit. 
     Furthermore, in the first aspect, a plurality of the connected imaging modules may be further provided, and the holding unit may surround and hold the side surfaces of the plurality of connected imaging modules. This brings about an effect that the side surfaces of the plurality of connected imaging modules are surrounded by the holding unit. 
     Furthermore, in the first aspect, the plurality of imaging modules may be connected after adjustment of optical axes. This brings about an effect that the optical axes are adjusted before the plurality of imaging modules is connected. 
     Furthermore, the second aspect of the present technology is a method of manufacturing an imaging device, the method including an attaching step of attaching an imaging module provided with an imaging element configured to image incident light introduced from an upper surface of a housing to a holding unit configured to surround and hold a side surface of the imaging module, the side surface being adjacent to the upper surface. This brings about an effect that the side surface of the imaging module is surrounded by the holding unit. 
     Furthermore, in the second aspect, a connecting step of connecting a plurality of the imaging modules may be further included, and the attaching step may include attaching the plurality of connected imaging modules to the holding unit configured to surround and hold the side surfaces of the plurality of connected imaging modules. This brings about an effect that the side surfaces of the plurality of connected imaging modules are surrounded by the holding unit. 
     Furthermore, in the second aspect, an optical axis adjusting step of adjusting optical axes of the plurality of imaging modules may be further included, and the connecting step may include connecting the plurality of imaging modules with the adjusted optical axes. This brings about an effect that the optical axes are adjusted before the plurality of imaging modules is connected. 
     Effects of the Invention 
     According to the present technology, an excellent effect of improving strength of an imaging module with an adjusted optical axis is exerted. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view illustrating a configuration example of an imaging device according to a first embodiment of the present technology. 
         FIG. 2  is a view illustrating a configuration example of an imaging module according to the embodiment of the present technology. 
         FIG. 3  is a cross-sectional view illustrating a configuration example of the imaging module according to the embodiment of the present technology. 
         FIG. 4  is a view illustrating a configuration example of a holding unit according to the first embodiment of the present technology. 
         FIG. 5  is a view illustrating a configuration example of a camera according to the first embodiment of the present technology. 
         FIG. 6  is a cross-sectional view illustrating a configuration example of the camera according to the first embodiment of the present technology. 
         FIG. 7  is a flowchart illustrating an example of a method of manufacturing the imaging device according to the first embodiment of the present technology. 
         FIG. 8  is a view illustrating a configuration example of an imaging device according to a second embodiment of the present technology. 
         FIG. 9  is a block diagram illustrating a schematic configuration example of a camera as an example of a device to which the present technology is applicable. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Next, embodiments for implementing the present technology (hereinafter, referred to as embodiments) will be described with reference to the drawings. In the drawings below, the same or similar parts are denoted by the same or similar reference numerals. Note that the drawings are schematic, and the dimensional ratios and the like of the respective parts do not always correspond to actual ones. Furthermore, it is needless to say that dimensional relationships and ratios are different among the drawings. Furthermore, the embodiments will be described in the following order. 
     1. First Embodiment 
     2. Second Embodiment 
     3. Application to Camera 
     1. First Embodiment 
     [Configuration of Imaging Device] 
       FIG. 1  is a view illustrating a configuration example of an imaging device according to a first embodiment of the present technology. An imaging device  100  in  FIG. 1  includes an imaging module  10  and a holding unit  20 . Note that the imaging device  100  in  FIG. 1  represents an example including two imaging modules  10 . 
     The imaging module  10  generates an image signal of an object. The imaging module  10  is configured such that an imaging element (an imaging element  17  to be described below) that images an object and an optical member that forms an image of light from the object on the imaging element are arranged in one module. In  FIG. 1 , the two imaging modules  10  are connected and held by the holding unit  20  to be described below. These two imaging modules  10  are bonded and connected to each other with an adhesive  31 . Furthermore, a signal cable  13  is connected to each of the imaging modules  10 , and an image signal from the imaging element and a control signal of the imaging element are transmitted. A connector  14  is arranged at an end of the signal cable  13 . Details of the configuration of the imaging module  10  will be described below. 
     The holding unit  20  holds the imaging module  10 . The holding unit surrounds and holds a side surface of the imaging module  10 . Here, the side surface of the imaging module  10  is a surface adjacent to an upper surface that is a surface to which light from an object is introduced in the imaging module  10 . Furthermore, the holding unit  20  in  FIG. 1  surrounds and holds side surfaces of the two connected imaging modules  10 . 
     As described above, in the imaging device  100  in  FIG. 1 , the two imaging modules  10  are held by the holding unit  20 , so that the two imaging modules  10  and the holding unit  20  can be handled as one component. The imaging device  100  provided with such two imaging modules  10  can be used for, for example, a camera that acquires a 3D image. Furthermore, for example, the imaging device  100  can be used for a camera that acquires images of the same object with visible light and infrared light. 
     [Configuration of Imaging Module] 
       FIG. 2  is a view illustrating a configuration example of the imaging module according to the embodiment of the present technology.  FIG. 2  is a view illustrating an appearance of the imaging module  10 . The imaging module  10  in  FIG. 2  includes a housing  11  and a lens barrel  12 . 
     The housing  11  is a housing that holds the lens barrel  12  and the imaging element. An opening is formed in an upper surface of the housing  11 , and the lens barrel  12  is arranged in the opening. 
     The lens barrel  12  supports a lens  15  and changes the position of the lens  15  to adjust a focal position. The lens barrel  12  is configured in a cylindrical shape, and the lens  15  is housed in a central portion. An actuator that changes the position of the lens  15  in an up-down direction is arranged around the lens  15 , and can focus on a surface of the imaging element. The lens barrel  12  corresponds to the above-described optical member. 
       FIG. 3  is a cross-sectional view illustrating a configuration example of the imaging module according to the embodiment of the present technology. A substrate  16  is arranged in a lower portion of the housing  11 , and an imaging element  17  sealed with a frame  18  and a cover glass  19  is mounted on a surface of the substrate  16 . At this time, the imaging element  17  is mounted on the substrate  16  by die bonding and connected to the substrate  16  by a bonding wire  41 . Note that a glass that blocks infrared light can be used for the cover glass  19 . The lens barrel  12  is arranged above the imaging element  17 , and the light from the object collected by the lens  15  is imaged on the surface of the imaging element  17 . Note that the lens  15  in  FIG. 3  schematically represents an arrangement of the lens in the lens barrel  12 . The lens barrel  12  can be configured to collect incident light by a plurality of lenses, for example. Furthermore, an optical axis of the imaging element  17  can be adjusted with the lens  15 . This can be performed by, for example, adjusting a mounting position and an angle of the imaging element  17  with respect to the substrate  16 . 
     [Configuration of Holding Unit] 
       FIG. 4  is a view illustrating a configuration example of the holding unit according to the first embodiment of the present technology. As illustrated in  FIG. 4 , the holding unit  20  configures a wall-shaped housing that surrounds the two connected imaging modules  10 . Furthermore, leg pieces  21  and  22  are arranged at an upper end and a lower end of the holding unit  20 , respectively. These leg pieces  21  and  22  configure horizontal surfaces with respect to the above-described wall-shaped housing. When the imaging device  100  is incorporated in a camera or the like, these leg pieces  21  and  22  are brought into contact with the housing of the camera or the like, so that the holding unit  20  is fixed. Further, by setting the holding unit  20  including the leg pieces  21  and  22  to be higher than the imaging module  10 , the strength in a state where an imaging device is incorporated in a camera  200  to be described below can be improved. 
     In a case where the two imaging modules  10  are connected and arranged on the holding unit  20 , the holding unit  20  has a rectangular shape. At this time, as illustrated in  FIG. 4 , the leg pieces  21  and  22  are arranged at a central portion of a long side of the rectangular shape and brought into contact with the housing of the camera or the like, so that the strength of a central portion of the imaging device  100  can be improved. Furthermore, as described in  FIG. 1 , the two imaging modules  10  are bonded to each other with the adhesive  31  arranged in the central portion, so that the strength in the central portion of the imaging device  100  can be further improved. Note that the shape of the holding unit  20  is not limited to this example. For example, a square or circular holding unit  20  can be used. Furthermore, a holding unit  20  having a projection used for positioning or the like when the imaging device  100  is attached to a device or the like can also be used. 
     The holding unit  20  can bond and hold the two imaging modules  10  with an adhesive, for example. Furthermore, the holding unit  20  can be configured using a metal. Note that the configuration of the holding unit  20  is not limited to this example. For example, the leg pieces  21  and  22  can be omitted to provide a simplified configuration. Furthermore, for example, a holding unit  20  configured using a resin can also be used. 
     [Configuration of Camera] 
       FIG. 5  is a view illustrating a configuration example of a camera according to the first embodiment of the present technology. A configuration of a device in which the imaging device  100  is arranged will be described using a camera  200  in  FIG. 5  as an example. For example, a mobile phone or a smartphone having a camera function corresponds to the camera  200 . The camera  200  includes a housing  201  having an opening  202 . The imaging device  100  is arranged inside the housing  201 , and images light from an object irradiated through the opening  202 . In  FIG. 5 , the dotted rectangle represents an outer shape of the imaging device  100 , and the solid circle represents the lens barrel  12 . 
       FIG. 6  is a cross-sectional view illustrating a configuration example of the camera according to the first embodiment of the present technology.  FIG. 6  is a view illustrating a cross section of a region of the camera  200  where the imaging device  100  is arranged. As illustrated in  FIG. 6 , the imaging device  100  is arranged in the housing  201 . The holding unit  20  is arranged in contact with upper and lower inner surfaces of the housing  201 . At this time, the leg pieces  21  and  22  are in contact with the housing  201 . Furthermore, the imaging module  10  is sandwiched between cushions  203  and  204 . The cushions  203  and  204  fix the position of the imaging module  10  and dissipate heat of the imaging module  10 . Note that the imaging modules  10  are bonded to each other with the above-described adhesive  31 , and is bonded to the holding unit  20  with adhesives  32  and  33 . As the adhesives  31  to  33 , for example, a photocurable resin, a thermosetting resin, a thermoplastic resin, a solder, or the like can be used. Hereinafter, a resin having both photocurable and thermosetting properties is assumed as the adhesives  31  to  33 . 
     By arranging the holding unit  20  in contact with the housing  201  as described above, arrangement of braces and the like for holding the upper and lower gaps of the housing  201  near the imaging device  100  can be omitted. Furthermore, gaps can be provided between upper and lower parts of the imaging module  10  and the housing  201 . With the configuration, the imaging module  10  can be protected from impact or the like applied to the camera  200 , and the strength of the imaging device  100  can be improved. Furthermore, since the imaging device  100  includes the holding unit  20 , a top plate, a bottom plate, and an adhesive for bonding the top plate and the bottom plate can be omitted, and a low-profile configuration can be achieved. 
     [Method of Manufacturing Imaging Device] 
       FIG. 7  is a flowchart illustrating an example of a method of manufacturing the imaging device according to the first embodiment of the present technology. First, an optical axis in a single eye is adjusted. That is, the optical axis of the imaging module  10  alone is adjusted (step S 100 ). The optical axis adjustment can be performed by six-axis adjustment of the imaging element  17  with respect to the lens  15 . Here, the six-axis adjustment is adjustment in which adjustment in three axes including axes (x, y) perpendicular to the optical axis and an axis (z) parallel to the optical axis is performed, and rotation angles around these three axes are adjusted. Furthermore, the adjustment can be performed by, for example, active alignment. This is a method of capturing an image for adjustment while changing the position of the imaging element  17  and confirming the image, and performing adjustment. 
     Next, optical axes in a compound eye are adjusted. That is, adjustment to align the optical axes of the two imaging modules  10  is performed (step S 101 ). This adjustment can be performed by adjusting the optical axis of one imaging module  10  of the two imaging modules  10  with reference to the optical axis of the other imaging module  10 . For example, the adjustment can be performed by adjusting the optical axis of the one imaging module  10  to become parallel to the optical axis of the reference imaging module  10 . 
     Next, the two imaging modules  10  with the adjusted optical axes are connected (step S 102 ). The connection can be performed by bonding the two imaging modules  10  with the adhesive  31  described with reference to  FIG. 6 . In a case of using the above-described resin having both the photocurable and thermosetting properties as the adhesive  31 , the above-described adjustment of optical axes in a compound eye is performed after the adhesive  31  is applied between the two imaging modules  10  for which the adjustment of the optical axis in a single eye has been performed. Thereafter, the connection can be performed by radiating ultraviolet rays to cure (temporarily cure) the adhesive  31 . 
     Next, the two connected imaging modules  10  are attached to the holding unit  20  (step S 103 ). The attachment can be performed by arranging the holding unit  20  at a position surrounding the side surfaces of the two connected imaging modules  10  and applying and curing the adhesives  32  and  33  described with reference to  FIG. 6 . Specifically, the attachment can be performed according to the following procedure. First, the holding unit  20  is arranged around the two connected imaging modules  10 , and the adhesives  32  and  33  are applied. The application can be performed by filling the gap between the two connected imaging modules  10  and the holding unit  20  with the above-described resin having both the photocurable and thermosetting properties, for example. Next, the optical axis adjustment between the two connected imaging modules  10  and the holding unit  20  is performed. The optical axis adjustment can be performed by adjusting four axes including the x, y, and z axes and the rotation angle (θ) around the z axis such that the position of a midpoint of the two lenses  15  of the two connected imaging modules  10  coincides with the center of the holding unit  20 . Next, the adhesives  32  and  33  are temporarily cured by radiating ultraviolet rays. Finally, the imaging device  100  is heated by a reflow furnace or the like, and the adhesives  31  to  33  are completely cured (main curing). Thereby, the two connected imaging modules  10  can be attached to the holding unit  20 . 
     The imaging device  100  can be manufactured by the above processes. As described above, the resin having both the photocurable and thermosetting properties is used for the adhesives  31  to  33 , and the adhesives  31  to  33  are temporarily cured by photocuring in the bonding of the side surfaces of the two connected imaging modules  10  and the bonding of the two connected imaging modules  10  and the holding unit  20 . The imaging modules  10  and the holding unit  20  after the temporary curing are heated, and the main curing by thermosetting of the adhesives  31  to  33  is collectively performed, so that the manufacturing process can be simplified. Furthermore, since the heating process can be reduced, occurrence of displacement of the optical axis due to heating can be reduced. 
     Note that the configuration of the imaging device  100  is not limited to this example. For example, a configuration including three or more imaging modules  10  can be adopted. 
     As described above, the imaging device  100  according to the embodiment of the present technology has the holding unit  20  that surrounds and holds the side surfaces of the plurality of connected imaging modules  10 , whereby protecting the imaging modules  10 , and improving the strength of the imaging device  100 . 
     2. Second Embodiment 
     The above-described imaging device  100  according to the first embodiment has included the two imaging modules  10 . In contrast, an imaging device  100  according to a second embodiment of the present technology is different from that of the first embodiment in including one imaging module  10 . 
     [Configuration of Imaging Device] 
       FIG. 8  is a view illustrating a configuration example of the imaging device according to the second embodiment of the present technology. The imaging device  100  in  FIG. 8  is different from the imaging device  100  described in  FIG. 1  in including one imaging module  10 . In the imaging device  100  in  FIG. 8 , a holding unit  20  surrounds and holds a side surface of the imaging module  10 . 
     The imaging device  100  in  FIG. 8  can be manufactured by a process in which steps S 101  and S 102  are omitted from the manufacturing process described in  FIG. 7 . 
     Since configurations of the imaging device  100  other than the above configuration are similar to those of the imaging device  100  described in the first embodiment of the present technology, description is omitted. 
     As described above, the imaging device  100  according to the second embodiment of the present technology has the holding unit  20  that surrounds and holds the side surface of the one imaging module  10 , whereby protecting the imaging module  10 , and improving the strength of the imaging device  100 . 
     3. Application to Camera 
     The present technology can be applied to various products. For example, the present technology may be implemented as an imaging device mounted on the camera described in the above embodiment. 
       FIG. 9  is a block diagram illustrating a schematic configuration example of a camera as an example of a device to which the present technology is applicable. A camera  1000  in  FIG. 9  includes a lens  1001 , an imaging element  1002 , an imaging control unit  1003 , a lens drive unit  1004 , an image processing unit  1005 , an operation input unit  1006 , a frame memory  1007 , a display unit  1008 , and a recording unit  1009 . 
     The lens  1001  is an imaging lens of the camera  1000 . The lens  1001  collects light from an object and causes the collected light to enter the imaging element  1002  to be described below to form an image of the object. 
     The imaging element  1002  is a semiconductor element that images the light from the object collected by the lens  1001 . The imaging element  1002  generates an analog image signal according to the radiated light, and converts the analog image signal into a digital image signal and outputs the digital image signal. 
     The imaging control unit  1003  controls imaging by the imaging element  1002 . The imaging control unit  1003  controls the imaging element  1002  by generating a control signal and outputting the control signal to the imaging element  1002 . Furthermore, the imaging control unit  1003  can perform autofocus in the camera  1000  on the basis of the image signal output from the imaging element  1002 . Here, the autofocus is a system that detects a focal position of the lens  1001  and automatically adjusts the focal position. As the autofocus, a method of detecting an image plane phase difference using a phase difference pixel arranged in the imaging element  1002  and detecting the focal position (image plane phase difference autofocus) can be used. Furthermore, a method of detecting a position where the contrast of an image becomes the highest as the focal position (contrast autofocus) can be applied. The imaging control unit  1003  adjusts the position of the lens  1001  via the lens drive unit  1004  on the basis of the detected focal position, and performs autofocus. Note that the imaging control unit  1003  can be configured by, for example, a digital signal processor (DSP) equipped with firmware. 
     The lens drive unit  1004  drives the lens  1001  on the basis of the control of the imaging control unit  1003 . The lens drive unit  1004  can drive the lens  1001  by changing the position of the lens  1001  using a built-in motor. 
     The image processing unit  1005  processes an image signal generated by the imaging element  1002 . This processing corresponds to, for example, demosaicing for generating an image signal of a missing color among image signals corresponding to red, green, and blue for each pixel, noise reduction for removing noise of the image signal, encoding of the image signal, and the like. The image processing unit  1005  can be configured by, for example, a microcomputer equipped with firmware. 
     The operation input unit  1006  receives an operation input from a user of the camera  1000 . As the operation input unit  1006 , for example, a push button or a touch panel can be used. The operation input received by the operation input unit  1006  is transmitted to the imaging control unit  1003  and the image processing unit  1005 . Thereafter, processing corresponding to the operation input, for example, processing such as imaging of the object is started. 
     The frame memory  1007  is a memory that stores a frame that is an image signal for one screen. The frame memory  1007  is controlled by the image processing unit  1005 , and holds frames in the course of image processing. 
     The display unit  1008  displays an image processed by the image processing unit  1005 . For the display unit  1008 , for example, a liquid crystal panel can be used. 
     The recording unit  1009  records an image processed by the image processing unit  1005 . For the recording unit  1009 , for example, a memory card or a hard disk can be used. 
     The camera to which the present invention is applicable has been described. The present technology can be applied to the lens  1001 , the imaging element  1002 , and the lens drive unit  1004  among the above-described configurations. Specifically, the imaging device  100  illustrated in  FIG. 1  can be applied to the lens  1001 , the imaging element  1002 , and the lens drive unit  1004 . By applying the imaging device  100 , the imaging element  1002  can be protected from impact or the like. 
     Note that, although the camera has been described as an example here, the technology according to the present invention may be applied to, for example, a monitoring device or the like. 
     Lastly, the description of each of the above embodiments is an example of the present technology, and the present technology is not limited to the above-described embodiments. Therefore, it goes without saying that various changes can be made according to design and the like even if the changes are other than the above-described embodiments as long as the changes do not depart from the technical idea of the present technology. 
     Furthermore, the processing procedures described in the above embodiments may be regarded as a method having these series of procedures, and also regarded as a program for causing a computer to execute these series of procedures and as a recording medium for storing the program. As the recording medium, for example, a compact disc (CD), a digital versatile disc (DVD), a memory card, or the like can be used. 
     Note that the present technology can also have the following configurations. 
     (1) An imaging device including: 
     an imaging module provided with an imaging element configured to image incident light introduced from an upper surface of a housing; and 
     a holding unit configured to surround and hold a side surface of the imaging module, the side surface being adjacent to the upper surface. 
     (2) The imaging device according to (1), further including: 
     a plurality of the imaging modules connected, in which 
     the holding unit surrounds and holds the side surfaces of the plurality of connected imaging modules. 
     (3) The imaging device according to (2), in which the plurality of imaging modules is connected after adjustment of optical axes. 
     (4) A method of manufacturing an imaging device, the method including: 
     an attaching step of attaching an imaging module provided with an imaging element configured to image incident light introduced from an upper surface of a housing to a holding unit configured to surround and hold a side surface of the imaging module, the side surface being adjacent to the upper surface. 
     (5) The method of manufacturing an imaging device according to (4), the method further including: 
     a connecting step of connecting a plurality of the imaging modules, in which 
     the attaching step includes attaching the plurality of connected imaging modules to the holding unit configured to surround and hold the side surfaces of the plurality of connected imaging modules. 
     (6) The method of manufacturing an imaging device according to (5), the method further including: 
     an optical axis adjusting step of adjusting optical axes of the plurality of imaging modules, in which 
     the connecting step includes connecting the plurality of imaging modules with the adjusted optical axes. 
     REFERENCE SIGNS LIST 
     
         
           10  Imaging module 
           11  Housing 
           12  Lens barrel 
           15 ,  1001  Lens 
           17 ,  1002  Imaging element 
           20  Holding unit 
           21 ,  22  Leg piece 
           31  to  33  Adhesive 
           100  Imaging device 
           200 ,  1000  Camera 
           201  Housing 
           1004  Lens drive unit