Abstract:
Provided are a method for manufacturing an imaging device at low cost while ensuring easiness in manufacturing, and the imaging device. In the imaging device, a diaphragm  14   a  can be used as a diaphragm by insert molding a metal plate material MP in a transparent resin material which forms a lens, a diaphragm as a separate member is not required to be assembled, and troubles in assembly are eliminated. Further, a shield of an imaging element can be grounded by assembling a lens array LA to an imaging element array IA while making a leg section  14   b  abut to an earth terminal T 1   g . Thus, wire connection by soldering is eliminated and troubles in assembly are eliminated.

Description:
RELATED APPLICATIONS 
     This is a U.S. National Phase Application under 35 U.S.C. 371 of International Application PCT/JP2008/056886, filed on Apr. 7, 2008. 
     This application claims the priority of Japanese Application No. 2007-108068 filed on Apr. 17, 2007, the entire content of which is hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a manufacturing method of a compact imaging device suitable for being installed in, for example, a mobile phone, and an imaging device. 
     BACKGROUND 
     In recent years, developments of mobile phones and handy personal computers (mobile personal computer) in which compact cameras are installed have been advanced. For example, the mobile phone provided with the compact camera can capture an image of the calling party as image data by a built-in camera and transmit the image data to an intended party. Such compact camera is generally configured with an image sensor and a lens. Namely the lens forms an optical image on the image sensor and the image sensor can create an electric signal corresponding to the optical image. 
     Meanwhile, further downsizing of the mobile phones and handy personal computers is being advanced, thus downsizing of the compact camera used in the above equipment is being required. To fulfill the demands of downsizing of such cameras, camera modules configured by integrating the lens and the camera module are being developed. 
     In Patent Document 1 (Unexamined Japanese Patent Application Publication No. 2004-200965), a camera module manufacturing method base on the following manufacturing processes is disclosed. In accordance with the following manufacturing processes of the prior art, an image sensor wafer configured by disposing a plurality of image sensor chips, and a lens array in a shape of a wafer configured by disposing a plurality of lenses having the same size as that of the image sensor chip are prepared first. After that, the lens array is bonded on a surface of the image sensor wafer. Further, the bonded wafers in which the image sensor wafer and the lens array are disposed are cut along cutting grooves so as to separate individual camera modules. Whereby, manufacturing processes are simplified.
     Unexamined Japanese Patent Application Publication No. 2004-200965   

     DISCLOSURE OF THE INVENTION 
     Problems to be Resolve by the Invention 
     Meanwhile, in accordance with progress of imaging elements of higher resolution, frequency of operation clock becomes higher which may negatively affects communication of the mobile phone. Therefore, there is a demand to cover a periphery of the imaging element with a conductive shield, however there is an issue of how to ground the shield. For example, in a technology of Patent Document 1, the periphery of the imaging element of each camera module after separating is covered by a housing, and the housing is connected with an earth terminal by soldering. However the above method is laborious. Also, in case a diaphragm of optical system is prepared and installed as a separate part, there is also a problem of laboriousness. 
     The present invention has one aspect to solve the above problems and an object of the present invention is to provide a manufacturing method to manufacture an imaging device economically while ensuring easiness of manufacturing. 
     Means to Resolve the Problems 
     An imaging device manufacturing method described in Claim  1  includes: 
     forming a plurality of openings and a plurality of leg sections at a metal plate; 
     forming a lens array through insert molding wherein the metal plate is inserted in a transparent resin which forms a lens; 
     forming an imaging element array wherein imaging elements having earth terminals are disposed in a shape of an array; 
     assembling the lens array with the imaging element array while contacting the leg section with the earth terminal; and 
     forming an imaging device provided with a pair of the lens and the imaging element by cutting the lens array and the imaging element array. 
     According to the present invention by molding the metal plate through insert molding to include the opening within the transparent resin material which from a lens, the opening can be used as a diaphragm without assembling an diaphragm as a separate member, thus labors of assembling can be saved. In addition, by assembling the lens array onto the imaging element array while contacting the leg section with the earth terminal, the shield of the imaging element can be grounded without connecting by soldering, thus labors of assembling can be saved. 
     The imaging device manufacturing method described in Claim  2  is based on that described in Claim  1  further characterized in that the lens of the lens array and the imaging element of the imaging element array are positioned within the prescribed range by the leg section in an optical axis direction. Whereby, for example, there is an advantage that only by assembling the lens array with the imaging element array while contacting the leg section to the earth terminal, focusing can be performed accurately. 
     The imaging device manufacturing method described in Claim  3  is based on that described in Claim  1  or  2  further characterized in that a bottom surface of the leg section of the lens array is grinded before assembling the lens array with the imaging element array. Whereby, focusing can be performed more accurately. 
     The imaging device manufacturing method described in Claim  4  is based on that described in any one of Claims  1  to  3  further characterized in that the lens array is formed through two-color molding using a transparent resin material to form the lens and a black color resin material to form a lens frame. 
     Whereby, labors to assemble the lens with the lens frame can be saved. 
     The imaging device manufacturing method described in Claim  5  is based on that described in any one of Claims  1  to  4  further characterized in that the resin material has a heat resistance property. Since the resin material has the heat resistance property, the soldering on the substrate through a solder reflow bath is possible. 
     The imaging device manufacturing method described in Claim  6  is based on that described in any one of Claims  1  to  5  further characterized in that the imaging device is provided with three leg sections at a circumference of one opening. Whereby, a preferable balance can be ensured. 
     The imaging device manufacturing method described in Claim  7  is based on that described in any one of Claims  1  to  6  further characterized in that a conductive paint is applied onto a circumference of the imaging device so that the conductive paint contacts a part of the metal plate exposed by cutting the lens array. Whereby, the conductive paint contacts with the metal plate and is connected with the earth terminal via the leg section. 
     An imaging device described in Claim  8  includes: 
     an imaging element mounted on the substrate, provided with a light receiving surface on which pixels are disposed; 
     a lens to form an image of an object on the light receiving surface of the imaging element; and 
     a conductive diaphragm member included in the lens, 
     wherein the diaphragm member is connected with an earth terminal of the substrate. 
     According to the present invention, by including the aforesaid conductive diaphragm member in the lens (for example, through insert molding), the diaphragm does not have to be installed as the separate member and the labor of installation can be saved. Further, by contacting a conductive diaphragm member with the earth terminal of the substrate, the shield of the imaging element can be grounded, thus installation of the shield member as a separate member is not necessary, which reduces number of the parts, compactifies the configuration and saves the labor of installation. 
    
    
     
       EFFECT OF THE INVENTION 
       According to the present invention, there are provided a manufacturing method to manufacture an economical imaging device while maintaining manufacturing easiness and an imaging device. 
         FIG. 1  is a cross-sectional view of an imaging device  50  related to the present embodiment. 
         FIG. 2  is a view observed from an arrow II direction in  FIG. 1 . 
         FIG. 3  is a diagram showing a process to manufacture an element unit. 
         FIG. 4  is a diagram showing a process to manufacture an element unit. 
         FIG. 5  is a diagram showing a process to manufacture an element unit. 
         FIG. 6  is a diagram showing a process to manufacture an element unit. 
         FIG. 7  is a diagram showing a process to manufacture an element unit. 
         FIG. 8  is a diagram showing a process to manufacture an element unit. 
         FIG. 9  is a diagram showing a part of an exemplary variation of an element unit. 
     
    
    
     DESCRIPTION OF THE SYMBOLS 
     
         
         
           
               11  lens 
               12  lens frame 
               13  conductive paint 
               14  metal plate 
               14   a  opening 
               14   b  leg section 
               50  imaging device 
               51  image sensor 
               51   a  photoelectric conversion section 
               51   c  through hole 
               51   d  conductive member 
               54  resin plate 
               55  conductive member 
             DB dicing blade 
             HB solder ball 
             IA imaging element array 
             LA lens array 
             LM lower mold 
             MP metal plate material 
             T 1  terminal 
             T 1   g  EARTH terminal 
             T 2  wiring layer 
             UM upper mold 
           
         
       
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described with reference to the drawings as follow.  FIG. 1  is a cross-sectional view of the imaging device  50  related to the present embodiment.  FIG. 2  is a view of the imaging element observed from an arrow II direction in  FIG. 1 . 
     An imaging device  50  has an image sensor  51  representing an imaging element. In  FIG. 1 , at a center section of the plane at a light receiving side of the image sensor  51 , there is formed a photoelectric conversion section  51   a  representing a light receiving section in which pixels (photoelectric conversion elements) are disposed two-dimensionally, and a signal processing circuitry section (unillustrated) is formed in a periphery thereof. 
     The signal processing circuitry section, not shown by figures in detail, is provided with a drive circuitry section to obtain the signal charge by sequentially driving each pixel, an A/D conversion section to convert each signal charge into a digital signal and a signal processing section to create an image signal output using the digital signal thereof, which are configured to communicate signals with an outside via a terminal TI (sensor pad) on the surface. 
     Also, a through hole  51   c  is formed from a plane surface (obverse surface) of a light receiving side of the image sensor  51  to a reverse surface. The image sensor  51  is grinded to be around 100 μm in a thickness, thus there is less possibility to be damaged when the through hole  51   c  is formed. A part of terminal T 1  in the obverse surface side and a part of a wiring layer T 2  on the reverse surface side are conducted each other via a conductive member  51   d  disposed in the through hole  51   c.    
     A resin plate  54  for reinforcement is bonded on a reverse surface of the image sensor  51 . In the resin plate  54 , a plurality of conductive member  55  are formed through insert molding. An upper end of the conductive member  55  is in contact with the wiring layer T 2  on the reverse surface side and a lower end side of the conductive member  55  is in contact with a solder ball HB. The solder ball HB is melted by passing through a high temperature solder reflow bath along with the imaging device  50  while being placed on an unillustrated substrate and establishes an electric conductance in respect to wiring of the substrate. Whereby, wiring from the substrate to the image sensor  51  can be accomplished. The image sensor  51  and the resin plate  54  configure an element unit. 
     The image sensor  51  converts the signal charge from the photoelectric conversion section  51   a  into the image signal and outputs to a prescribed circuitry on the substrate via the conductive member  55 . Incidentally, the imaging element is not limited to the CMOS type image sensor and a CCD and other types can be utilized. 
     In  FIG. 1 , a lens frame  12  in a shape of a cylinder having the heat resistance property formed by a black resin material is in contact with a circumference of the image sensor  51  at a lower end thereof. At an upper part of inside the lens frame  12 , a lens  11  having heat resistance property is formed with a transparent resin, and at an outer circumference of the lens frame  12 , a conductive paint  13  is applied. Inside the lens frame  12  and the lens  11 , a metal plate  14  is inserted, and an opening  14   a  of the metal plate  14  configures an aperture of the lens  11 . 
     Next, a manufacturing method of the imaging device related to the present embodiment will be described as follow.  FIGS. 3 to 8  are diagrams to show manufacturing processes of the imaging device  50 . For convenience, in  FIGS. 5 to 7 , only two lenses are shown, however, in practice, the lenses are disposed in an array as  FIG. 3  shows. First, a metal plate material MP is formed by press work to punch out a plurality of the openings  14   a  in a shape of an array, and at the same time, leg sections  14   b  are formed by punching and bending as  FIG. 4  shows.  FIG. 4  is a magnified view of the metal plate material MP. Incidentally, at the circumference of one opening  14   a , three log sections  14   b  having a prescribed length are formed, extending downward in parallel. 
     Next, as  FIG. 5  shows, by disposing the metal plate material MP having been pressed in an upper mold UM and a lower mold LM, a lens array LA including the metal plate material MP is formed through insert molding. When this occurs, the lens  11  and the lens frame  12  can be formed with different resin materials using tow-color molding which is disclosed in Unexamined Japanese Patent Application Publication No. 2007-1365, wherein at least the opening  14   a  is included in the transparent resin material. When this occurs, the leg sections  14   b  are not protruding from the lower surface of the lens array LA but only the front end of the leg thereof is exposed. Here, by regulating a length L 1  of the leg section  14   b , the lower surface of the lens array LA can contact with an upper surface of an imaging element array IA, whereby the image sensor  51  of the imaging element array IA corresponding to each lens  11  of the lens array LA can be positioned in the prescribed range in an optical axis direction, and as a result, a job such as focusing can be simplified. Incidentally, the prescribed range means the range of about ±F×2P (F: lens F number, P: pixel pitch of imaging element) in an air equivalent length, in which a deviation between the light receiving surface of the image sensor  51  and an imaging point of the lens  11  falls. For positioning within the prescribed range, the lower surface of the lens array LA can be grinded. 
     Also, the lens  11  and the lens frame  12  can be formed integrally with a transparent resin, and a part of the lens except an opening for photographing is printed by inkjet with non-transparent black ink so as to form a lese array LA. 
     In case, the lower surface of the lens array LA and an upper surface of the imaging element array IA to be described are bonded each other with an adhesive, as  FIG. 9  shows, it is desirable to extrude the leg section  14   b  from the lower surface of the lens array LA by an amount equivalent to a thickness of the adhesive. In the above case, first, the leg section  14   b  is extruded so that the extruding amount exceeds the thickness d, then after insert molding, the extruding amount can be adjusted to the thickness d by grinding the lower end of the leg section  14   b  so as to position the leg section  14   b  within the prescribed range. 
     On the other hand, a plurality of imaging elements are formed in the shape of the array and the imaging element array IA backed up by a resin plate  54  is formed in a separate process. Then as  FIG. 6  shows, the lens array LA and the imaging element array IA are bonded. When this occur, the three leg sections  14   b  come into contact in a balanced manner with three earth terminals T 1   g  among the terminals T 1  disposed at the circumference of the image sensor  51  (refer to  FIG. 2 ). 
     Thereafter, as  FIG. 7  shows, the lens array LA and the imaging element array IA having been bonded are cut by a rotating dicing saw to separate into individual imaging devices which are respectively provided with a pair of the lens  11  and an imaging sensor  51  (imaging element). The metal plate  14  cut at that time is exposed at the circumference of the imaging device. 
     Further, as  FIG. 8  shows, by applying the conductive paint  13  at the outer circumference of the imaging device, the conductive paint  13  covers the outer circumference of the lens frame  12 . When this occurs, since the conductive paint  13  contacts with the exposed metal plate  14  as well, the conductive paint  13  communicates with the earth terminal Tg 1  via the leg sections  14   b . Whereby, since the circumference of the image sensor  51  is surrounded by the conductive paint  13 , highly effective shielding is realized. 
     Incidentally, instead of the conductive paint  13 , a metal cylinder can be fitted. 
     After that, the unillustrated substrate, on which solder ball HB intervenes, is conveyed to the reflow bath so as to carry out installation of the imaging device  50 . 
     According to the present embodiment, by insert molding of the metal plate material MP so as to include the opening  14   a  in the transparent resin, the opening  14   a  serves as a diaphragm, thus a separate member is not necessary to be assembled as the diaphragm. Whereby the labor of assembling can be saved. Further, by assembling the lens array LA with the imaging element array IA while contacting the leg section  14   b  with the terminal T 1   g , the shield of the imaging element can be grounded, which also saves the labor of connecting wires by soldering, thus the labor of assembling can be saved. In addition, by adjusting the length L 1  of the leg section  14   b  in advance, the lens  11  and the image sensor  51  can be positioned in the prescribed range in the optical axis direction, whereby only by bonding the lens array LA with the imaging element array IA, the imaging sensor  51  can be disposed at a focus position of the lens  11 . Therefore, the labor of adjustment can be saved. 
     In the forgoing, while the present invention has been described with reference to the embodiments, it is to be understood that the present invention is not limited to the embodiments thereof and changes and variations may be made. The imaging lens can be configured with a single lens or a plurality of lenses.