Abstract:
To obtain an imaging unit, a lens barrel, and a portable terminal which can effectively suppress spring-back of solid-state imaging elements, while facilitating height lowering thereof. An imaging unit includes: a solid-state imaging element; and an imaging lens for forming a subject image on a photoelectric conversion part of the solid-state imaging element. An imaging surface of the solid-state imaging element is curved in a manner that a peripheral side is inclined toward an object side relative to a screen center. The imaging lens constrains the solid-state imaging element to prevent a radius of curvature of the imaging surface from varying. Thus, field curvature, distortion aberration, and comatic aberration are appropriately corrected.

Description:
TECHNICAL FIELD 
       [0001]    The present technology relates to an imaging unit, a lens barrel, and a portable terminal. Specifically, it relates to an imaging unit, a lens barrel, and a portable terminal each including: a solid-state imaging element which is a solid-state imaging element such as a CCD image sensor or a CMOS image sensor and has a curved imaging surface; and an imaging lens preferable thereto. 
       BACKGROUND ART 
       [0002]    In recent years, there are widely known small-sized imaging apparatuses using solid-state imaging elements such as a CCD (charged coupled device) or CMOS (Complementary Metal Oxide Semiconductor) image sensor. Such small-sized imaging apparatuses are now mounted onto portable terminals such as cellular phones, PDAs (Personal Digital Assistant) and the like, as well as notebook personal computers and the like, allowing not only audio information but also image information to be mutually transmitted to and from remote sites. 
         [0003]    With solid-state imaging elements used for such imaging apparatuses, the pixel size becomes smaller recently to increase the number of pixels and achieve size reduction. Furthermore, it has become possible to curve the imaging surface, whereby a small-sized, high-performance imaging lens which is most suitable for such an imaging element can be obtained. 
         [0004]    Patent Literature 1 discloses an imaging apparatus with a curved solid-state imaging element. Curving a solid-state imaging element into a polynomial surface shape corrects field curvature and distortion aberration occurring on the lens in a well-balanced manner, whereby a small-sized, high resolution imaging apparatus is provided. However, Patent Literature 1 does not disclose a specific method for curving the solid-state imaging element into a polynomial surface shape. 
       CITATION LIST 
     Patent Literature 
       [0005]    Patent Literature 1: JP 2004-356175A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    As a result of intensive studies by the inventors of the present application, a method has been found which compresses a solid-state imaging element from the outer peripheral side so as to curve the imaging surface into a polynomial surface shape. However, the solid-state imaging element compressed from the outer peripheral side is elastically deformed, and therefore a force which acts to restore the shape to a plane occurs due to so-called spring-back. On the other hand, it is also conceivable to provide a beam on the back side of the solid-state imaging element so as to suppress spring-back of the solid-state imaging element. However, there is a problem that the above solution is not preferable because it is desired to make the length in the optical axis direction of the imaging unit as short as possible (height lowering) when mounting the solid-state imaging element on a portable terminal such as a smart phone. 
         [0007]    The present technology, which has been made in view of the aforementioned problem, is directed to obtain an imaging unit, a lens barrel, and a portable terminal which can effectively suppress spring-back of solid-state imaging elements, while facilitating height lowering thereof. 
       Solution to Problem 
       [0008]    A first aspect of the present technology, which has been made in view of the above problem, is an imaging unit including: a solid-state imaging element; and an imaging lens for forming a subject image on a photoelectric conversion part of the solid-state imaging element. An imaging surface of the solid-state imaging element is curved in a manner that a peripheral side is inclined toward an object side relative to a screen center. The imaging lens constrains the solid-state imaging element to prevent a radius of curvature of the imaging surface from varying. 
         [0009]    According to the present technology, the imaging lens constrains the solid-state imaging element to prevent the radius of curvature of the imaging surface from varying so that, even when curving of the imaging surface of the solid-state imaging element causes spring-back, the radius of curvature of the imaging surface is maintained by resisting thereto, whereby field curvature, distortion aberration, and comatic aberration can be appropriately corrected. In addition, suppressing spring-back of the solid-state imaging element using the imaging lens at the object side of the solid-state imaging element allows downsizing and height lowering. Although it is assumed here that the curved shape of the imaging surface according to the present technology is curved in a manner that both the short side and the long side of the screen are similarly inclined to the object side toward the periphery of the screen, the shape need not necessarily be a spherical one, and may be any surface shape which can be expressed by a numerical formula, such as an aspherical, a paraboloidal, or an XY-polynomial one, and therefore it is possible to enhance the performance all over the screen by employing a shape that fits the shape of the field curvature generated in the lens system. 
         [0010]    In the first aspect, an optical surface or a flange part of the imaging lens may abut on a peripheral part of the imaging surface of the solid-state imaging element. 
         [0011]    The optical axis of the imaging lens is allowed to conform to the center of the solid-state imaging element by causing the optical surface or the flange part of the imaging lens to abut on the peripheral part of the imaging surface of the solid-state imaging element to exhibit a centering function. In addition, causing the optical surface or the flange part of the imaging lens to abut on the peripheral part of the imaging surface of the solid-state imaging element allows the interval between the imaging lens and the imaging surface of the solid-state imaging element to be precisely defined. Here, the optical surface includes the surface outside the effective diameter. 
         [0012]    In the first aspect, a space between the imaging lens and the solid-state imaging element may be sealed. 
         [0013]    Accordingly, it is possible to suppress sticking of foreign substance such as dust to the imaging surface. In addition, it is also possible to provide a medium other than the air layer such as liquid between the imaging lens and the solid-state imaging elements, whereby the optical characteristic can be improved. 
         [0014]    In the first aspect, when seen from an optical axis direction, a portion of the imaging lens may extend from the solid-state imaging element in a direction orthogonal to an optical axis, a portion of the solid-state imaging element may extend from the imaging lens in a direction orthogonal to the optical axis, and wire connection for transmitting signals to an external circuit may be made to the portion of the solid-state imaging element. 
         [0015]    Accordingly, wire connection of the solid-state imaging element is not prevented even when a portion of the imaging lens constrains the solid-state imaging element so as to extend in a direction orthogonal to the optical axis. 
         [0016]    A second aspect of the present technology is an imaging unit including: a solid-state imaging element; and an imaging lens for forming a subject image on a photoelectric conversion part of the solid-state imaging element. An imaging surface of the solid-state imaging element is curved in a manner that a peripheral side is inclined toward an object side relative to a screen center. A frame member that suppresses parts other than the imaging surface of the solid-state imaging element is provided between the imaging lens and the solid-state imaging element to prevent a radius of curvature of the imaging surface from varying, and subject light which has passed through the imaging lens passes through the frame member and forms an image on the image forming surface. 
         [0017]    According to the present technology, a frame member that suppresses parts other than the imaging surface of the solid-state imaging element is provided between the imaging lens and the solid-state imaging element to prevent the radius of curvature of the imaging surface from varying so that, even when curving of the imaging surface of the solid-state imaging element causes spring-back, the radius of curvature of the imaging surface is maintained by resisting thereto, whereby field curvature, distortion aberration, and comatic aberration can be appropriately corrected. In addition, spring-back of the solid-state imaging element is suppressed using the frame member provided between the solid-state imaging element and the imaging lens, which also allows downsizing and height lowering. Subject light which has passed through the imaging lens passes through the frame member and forms an image on the image forming surface, without preventing image capturing. 
         [0018]    In addition, a micro lens may be provided on the image-side optical surface of the imaging lens in the first or second aspect. 
         [0019]    Accordingly, production of the solid-state imaging element becomes easy. 
         [0020]    In addition, a diameter of the micro lens may become gradually larger from the optical axis side toward the peripheral side in the first or second aspect. 
         [0021]    Accordingly, it is possible to resolve the inconvenience when forming an image on the curved imaging surface of the solid-state imaging element with a micro lens provided on the image-side optical surface of the imaging lens. 
         [0022]    In addition, a color filter may be provided on the image-side optical surface of the imaging lens in the first or second aspect. 
         [0023]    Accordingly, production of the solid-state imaging element becomes easy. 
         [0024]    A third aspect of the present technology is a lens barrel including the imaging unit in the first or second aspect. 
         [0025]    A fourth aspect of the present technology is a portable terminal including the imaging unit in the first or second aspect. 
       Advantageous Effects of Invention 
       [0026]    According to the present technology, it is possible to obtain an imaging unit, a lens barrel, and a portable terminal which can effectively suppress spring-back of a solid-state imaging element while facilitating height lowering thereof. The effects described herein are not limiting, and any of the effects described in the disclosure may be effective. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0027]      FIG. 1  is a cross-sectional view of an imaging unit  10  according to a first embodiment. 
           [0028]      FIG. 2  is an enlarged cross-sectional view of a portion of the imaging unit  10 . 
           [0029]      FIG. 3  illustrates a state in which the imaging unit  10  is installed on a smart phone  100  which is a portable terminal. 
           [0030]      FIG. 4  is a control block diagram of the smart phone  100 . 
           [0031]      FIG. 5  is a cross-sectional view of an imaging unit  10 A according to a second embodiment. 
           [0032]      FIG. 6  is a cross-sectional view of an imaging unit  10 B according to a third embodiment. 
           [0033]      FIG. 7  is a cross-sectional view of an imaging unit  10 C according to a fourth embodiment. 
           [0034]      FIG. 8  is a cross-sectional view of an imaging unit  10 D according to a fifth embodiment. 
           [0035]      FIG. 9  is a cross-sectional view of an imaging unit  10 E according to a sixth embodiment. 
           [0036]      FIG. 10  is a cross-sectional view of an imaging unit  10 F according to a seventh embodiment. 
           [0037]      FIG. 11  illustrates an imaging unit  10 G according to an eighth embodiment. 
           [0038]      FIG. 12  illustrates an imaging unit  10 H according to a ninth embodiment. 
           [0039]      FIG. 13  illustrates an imaging unit  10 J and an application thereof according to a tenth embodiment. 
           [0040]      FIG. 14  is a cross-sectional view of an imaging lens of Example 1. 
           [0041]      FIG. 15  illustrates an aberration (spherical aberration, astigmatic aberration, distortion aberration) of the imaging lens of Example 1. 
           [0042]      FIG. 16  illustrates meridional comatic aberration of Example 1. 
           [0043]      FIG. 17  is a cross-sectional view of an imaging lens of Example 2. 
           [0044]      FIG. 18  illustrates the aberration (spherical aberration, astigmatic aberration, distortion aberration) of the imaging lens of Example 2. 
           [0045]      FIG. 19  illustrates meridional comatic aberration of Example 2. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0046]    In the following, modes (referred to as embodiments below) for implementing the present technology will be described. 
       First Embodiment 
       [0047]      FIG. 1  is a cross-sectional view of an imaging unit  10  according to a first embodiment.  FIG. 2  is an enlarged cross-sectional view of a portion of the imaging unit  10 . 
         [0048]    As illustrated in  FIG. 1 , the imaging unit  10  includes a CMOS imaging element  11 , an imaging lens  12 , a housing  13 , and a substrate  14  holding the imaging element  11 , which are integrally formed. The CMOS imaging element  11  is a solid-state imaging element having an imaging surface  11   c  as a photoelectric conversion part. The imaging lens  12  is a lens for capturing a subject image on an imaging surface  11   c  on the imaging element  11 . The housing  13  includes a light-shielding member having an aperture for receiving light incident from the object side. 
         [0049]    The intermediate product of the imaging element  11  has a flat-plate shape and is curved into a hemispherical shape with a predetermined radius of curvature by being compressed from the outer peripheral side, and the imaging element  11  includes a central curved part  11   a  and a flat-plate part  11   b  around the curved part  11   a.  The imaging surface  11   c  is formed in the central part of the surface on the light receiving side of the curved part  11   a  as a light-receiving part having pixels (photoelectric conversion elements) arranged two-dimensionally, and a signal processing circuit (not illustrated) is formed around the imaging surface  11   c.  The signal processing circuit includes a drive circuit part which sequentially drives each pixel to obtain signal electric charge, an A/D conversion part which converts each signal electric charge into a digital signal, and a signal processing part which forms an image signal output using the digital signal, and the like. The imaging element is not limited to the aforementioned CMOS image sensor, and other types of elements such as CCD may be applied thereto. In addition, when not explicitly stated, a micro lens and a color filter are formed on the imaging surface  11   c,  although not illustrated. 
         [0050]    The imaging element  11  has the flat-plate part  11   b  attached to the substrate  14  having an aperture  14   a  so as to accommodate a portion of the curved part  11   a  in the aperture  14   a.  A pad  11   d  is formed around the flat-plate part  11   b  of the imaging element  11 , and the substrate  14  and the pad  11   d  are connected via a bonded wire  15  (wire connection). The wire  15  connects the imaging element  11  and an external circuit (for example, a control circuit included in an upper level device having an imaging unit installed therein) which is not illustrated. Accordingly, it is possible to receive voltage or clock signals for driving the imaging element  11  supplied from an external circuit, or output digital YUV signals to the external circuit. 
         [0051]    The imaging lens  12  is provided at the imaging surface  11   c  side of the imaging element  11 . As illustrated in  FIG. 2 , the imaging lens  12  has an image-side optical surface  12   a  arranged spaced apart by a predetermined distance (or in close contact therewith) in the optical axis direction relative to the imaging surface  11   c,  a flange part  12   b  around the image-side optical surface  12   a,  and a protrusion  12   c  provided between the image-side optical surface  12   a  and the flange part  12   b.  Causing the image-side face of the flange part  12   b  of the imaging lens  12  to abut on the flat-plate part  11   b  formed around the imaging surface  11   c  of the imaging element  11  allows the image-side optical surface  12   a  to be positioned relative to the imaging surface  11   c  in the optical axis direction. On the other hand, causing the protrusion  12   c  of the imaging lens  12  to abut on the curved part  11   a  around the imaging surface  11   c  of the imaging element  11  allows the imaging lens  12  to be positioned relative to the imaging surface  11   c  in a direction orthogonal to the optical axis. It is also possible to cause the image-side optical surface  12   a  itself of the imaging lens  12  to abut on the periphery of the imaging surface  11   c  of the imaging element  11 . 
         [0052]    In other words, according to the present embodiment, the radius of curvature of the imaging surface  11   c  is maintained by constraining the imaging element  11  by adhesively fixing the imaging lens  12  to the imaging element  11 , and maintaining its shape by resisting the spring-back occurring in the imaging element  11 . Accordingly, field curvature, distortion aberration, and comatic aberration can be appropriately corrected. In addition, spring-back of the imaging element  11  is suppressed using the imaging lens  12  at the object side of the imaging element  11 , whereby downsizing and height lowering also become possible. 
         [0053]    Applying an adhesive around the entire periphery of the imaging element  11  allows sealing the space between the imaging lens  12  and the imaging element  11 . Accordingly, it is possible to suppress sticking of foreign substance such as dust to the imaging surface  11   c.  In addition, a medium other than air may be filled in the sealed space. 
         [0054]    The substrate  14  has a housing  13  attached thereto, which shields the light around the imaging lens  12  and holds the imaging lens  12 . 
         [0055]    The operation of the aforementioned imaging unit  10  will be described.  FIG. 3  illustrates a state in which the imaging unit  10  is installed on a smart phone  100  which is a portable terminal. In addition,  FIG. 4  is a control block diagram of the smart phone  100 . 
         [0056]    The imaging unit  10  is installed at a position corresponding to the lower part of the liquid crystal display part, with the object side end face of the housing  13  being provided on the back side (see  FIG. 3( b ) ) of the smart phone  100 , for example. 
         [0057]    The imaging unit  10  is connected to a control part  101  of the smart phone  100  via an external connection terminal (the arrow in  FIG. 4 ,), and outputs image signals such as luminance signals or color difference signals to the control part  101  side. 
         [0058]    On the other hand, the smart phone  100  includes, as illustrated in  FIG. 4 , the control part (CPU)  101 , an input part  60 , a display part  65 , a wireless communication part  80 , a storage part (ROM)  91 , and a temporary storage part (RAM)  92 . The control part (CPU)  101  is configured to collectively control each part and execute a program according to each process. The input part  60  is configured to accept indications of switches such as the power source, numbers or the like, input via a touchpad. The display part  65  is configured to display captured images, or the like, in addition to predetermined data on the liquid crystal panel. However, the touch panel  70  works as both the liquid crystal panel of the display part and the touchpad of the input part. The wireless communication part  80  is configured to realize various information communication to and from an external server. The storage part (ROM)  91  is configured to store system programs and various processing programs of the smart phone  100  and a variety of required data such as terminal IDs. The temporary storage part (RAM)  92  is a work area for temporarily storing various processing programs to be executed by the control part  101  or data, processing data, imaging data obtained by the imaging unit  10  or the like. 
         [0059]    The smart phone  100  operates by manipulation of the input key part  60 , i.e., and can drive the imaging unit  10  to capture an image by touch of the icon  71 , or the like, being displayed on the touch panel  70 . Subject light forms an image on the imaging surface  11   c  of the imaging element  11  via the imaging lens  12 . The image signal converted by the imaging unit  10  is stored in the storage part  92  by the control system of the smart phone  100 , or displayed on the touch panel  70 , and furthermore, transmitted to the outside as video information via the wireless communication part  80 . 
       Second Embodiment 
       [0060]      FIG. 5  is a cross-sectional view of an imaging unit  10 A according to a second embodiment, with the housing being omitted. In the present embodiment, a substrate  14 A has a cylindrical concave part  14   b,  with a portion of the imaging element  11  being accommodated in the concave part  14   b.  The rest of the configuration is similar to the aforementioned embodiment. 
       Third Embodiment 
       [0061]      FIG. 6  is a cross-sectional view of an imaging unit  10 B according to a third embodiment, with the housing being omitted. In the present embodiment, the entire back side (the side opposite to the imaging lens  12 ) of the block-shaped imaging element  11  B is adhesively fixed to a parallel flat-plate substrate  14 B, and the flange part  12   b  of the imaging lens  12  abuts on the object side face of the flat-plate part  11   b  of the imaging element  11 A to be adhesively fixed thereto. The rest of the configuration is similar to the aforementioned embodiment. 
       Fourth Embodiment 
       [0062]      FIG. 7  is a cross-sectional view of an imaging unit  10 C according to a fourth embodiment, with the housing being omitted. In the present embodiment, a portion of the imaging lens  12 C is accommodated in the aperture  14   a  of the substrate  14 . The imaging element  11 C is adhesively fixed to the flange part  12   b  of the imaging lens  12 , being supported relative to the substrate  14  thereby. The wire  15  extending from the back side of the substrate  14  is connected to the pad  11   d  provided on the back side (the side opposite to the imaging lens  12 C) of the flat-surface part  12   b  of the imaging element  11 C. The rest of the configuration is similar to the aforementioned embodiment. 
       Fifth Embodiment 
       [0063]      FIG. 8  is a cross-sectional view of an imaging unit  10 D according to a fifth embodiment, with the housing being omitted. The difference of the present embodiment lies in that an imaging lens  12 D, formed by three lenses, is fixed to the substrate  14  via a combination holder  16  so that the inter-lens distance is adjustable. The rest of the configuration is similar to the aforementioned embodiment. 
       Sixth Embodiment 
       [0064]      FIG. 9  is a cross-sectional view of an imaging unit  10 E according to a sixth embodiment, with the housing being omitted. In the present embodiment, an annular frame member  17  is provided between the imaging lens  12  and the imaging element  11 . The frame member  17 , having an aperture  17   a  and a protrusion  17   c  protruding toward the imaging element  11  side, functions in the present embodiment as a holder for fixing the imaging lens  12  to a housing (not illustrated), and also functions as means for suppressing spring-back of the imaging element  11 . 
         [0065]    The imaging lens  12  can be positioned relative to the imaging surface  11   c  in the optical axis direction via the frame member  17  by causing the image-side face of the frame member  17  to abut on the flat-plate part  11   b  formed around the imaging surface  11   c  of the imaging element  11 . On the other hand, the imaging lens  12  can be positioned relative to the imaging surface  11   c  in a direction orthogonal to the optical axis via the frame member  17  by causing the protrusion  17   b  of the frame member  17  to abut on the curved part  11   a  around the imaging surface  11   c  of the imaging element  11 . Subject light having passed through the imaging lens  12  enters the imaging surface  11   c  via the aperture  17   a  of the frame member  17 . Here, the imaging lens  12  and the frame member  17  may be separated from each other. 
       Seventh Embodiment 
       [0066]      FIG. 10  is a cross-sectional view of an imaging unit  10 F according to a seventh embodiment, with the housing being omitted. In the present embodiment, micro lenses  18  are formed on the image-side optical surface  12   a  of the imaging lens  12 F, in a manner arranged in a matrix corresponding to the pixels of the imaging surface  11   c.  Accordingly, it becomes easy to form the imaging element  11  having the curved imaging surface  11   c.  The rest of the configuration is similar to the aforementioned embodiment. 
       Eighth Embodiment 
       [0067]      FIG. 11( a )  is a partial cross-sectional view of an imaging unit  10 G according to an eighth embodiment (only a portion of the micro lenses  18  are illustrated), and  FIG. 11( b )  is a view of the micro lenses  18  and the imaging surface  11   c  which are overlapped in the optical axis direction. In the present embodiment, the further away from the center, the larger the pixel size of the imaging surface  11   c  of the imaging element  11 G is, and correspondently, the further away from the optical axis, the larger the diameter of the micro lens  18  formed in the image-side optical surface  12   a  of the imaging lens  12 G is. Accordingly, light-gathering characteristics can be enhanced. The rest of the configuration is similar to the aforementioned embodiment. Here, a color filter may be provided on the image-side optical surface  12   a.    
       Ninth Embodiment 
       [0068]      FIG. 12( a )  is a view of an imaging lens  12 H for use in a ninth embodiment, seen from the optical axis direction.  FIG. 12( b )  is a view of an imaging element  11 H for use in the ninth embodiment, seen from the optical axis direction.  FIG. 12( c )  is a view of the imaging lens  12 H and the imaging element  11 H which are overlapped in the optical axis direction. In the present embodiment, the flange part  12   b  of the imaging lens  12 H extends from the imaging element  11 H in a direction orthogonal to the optical axis (vertical direction in  FIG. 12 ), as illustrated in  FIG. 12( c ) . A portion of the flat-surface part  11   b  of the imaging element  11 H extends from the imaging lens  12 H in a direction orthogonal to the optical axis (lateral direction in  FIG. 12 ). The flat-surface part  11   b  spreading out of the imaging lens  12  of the imaging element  11 H has the pad  11   d  provided thereon, which is connected by the wire  15  (only a portion is illustrated). The rest of the configuration is similar to the aforementioned embodiment. 
       Tenth Embodiment 
       [0069]    In the imaging unit  10 J according to the present embodiment, the image-side optical surface  12   a  of the imaging lens  12 J is attached to the curved imaging surface  11   c  of the imaging element  11 H, as illustrated in  FIG. 13 . Although micro lenses and a color filter are provided between the image-side optical surface  12   a  and the imaging surface  11   c,  they need not necessarily be provided. The imaging unit  10 J is provided in a tubular lens barrel  20 . Here, a group of other lenses  21  can be arranged at the object side of the imaging lens  12 J in the lens barrel  20  by extending the lens barrel  20  toward the object side, as illustrated in  FIG. 13( a ) . 
         [0070]    In addition, as illustrated in  FIG. 13( b ) , in exchange for shortening the lens barrel  20  having the imaging unit  10 J built therein, the lens barrel  20  may be coupled to another long lens barrel  23  having another group of lenses  21  built therein, via an annular coupling member  22 . Accordingly, it is possible to provide a lens barrel with an imaging element for which any focal length may be selected. As a further application, it is conceivable to arrange the imaging unit  10 J and the lens barrel  20  inside a camera body  24 , as illustrated in  FIG. 13( c ) . Accordingly, it becomes possible to use a desired interchangeable lens by detachably coupling, via the annular joint member  22 , the lens barrel  20  to another lens barrel  23  having a telephoto lens  21  built therein. In addition, as illustrated in  FIG. 13( d ) , it is also possible to mount the imaging unit  10 J on the low-profile smart phone  100  as illustrated in  FIG. 3 , by coupling, via the annular coupling member  22 , the lens barrel  20  to another short lens barrel  26  having a wide-angle lens  25  built therein. In other word, it becomes possible to mount the imaging unit  10 J on any digital camera or smart phone, regardless of the model, with the basic configuration of the imaging unit  10 J remaining unchanged. 
       EXAMPLES 
       [0071]    Next, Examples of the imaging lens suitable for the aforementioned embodiments will be described. However, the present invention is not limited by the Examples described below. The symbols used in each Example are as follows:
   f: focal length of entire imaging lens system   fB: back focus   F: F number   2Y: imaging surface diagonal length of solid-state imaging element   ENTP: entrance pupil position (distance from first surface to entrance pupil position)   EXTP: exit pupil position (distance from imaging surface to exit pupil position)   H1: front side main point position (distance from first surface to front side main point position)   H2: rear side main point position (distance from last surface to rear side main point position)   R: radius of curvature   D: axial surface separation   Nd: refractive index relative to d-line of lens material   vd: Abbe number of lens material   
 
         [0084]    In each Example, a surface with “*” after each surface number is an aspheric surface, and the aspheric surface is expressed by the following “Math. 1”, with the apex of the surface being the origin, the X-axis taken in the optical axis direction, and the height perpendicular to the optical axis denoted by h. 
         [0000]    
       
         
           
             
               
                 
                   X 
                   = 
                   
                     
                       
                         
                           h 
                           2 
                         
                         / 
                         R 
                       
                       
                         1 
                         + 
                         
                           
                             1 
                             - 
                             
                               
                                 ( 
                                 
                                   1 
                                   + 
                                   K 
                                 
                                 ) 
                               
                                
                               
                                 
                                   h 
                                   2 
                                 
                                 / 
                                 
                                   R 
                                   2 
                                 
                               
                             
                           
                         
                       
                     
                     + 
                     
                       ∑ 
                       
                         
                           A 
                           i 
                         
                          
                         
                           h 
                           i 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Math 
                     . 
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
         [0000]    where,
   Ai: i-th order aspheric coefficient   R: radius of curvature   K: conic constant.   
 
       Example 1 
       [0088]    Lens data are listed in Table  1 . In the following (including lens data in the Table), it is assumed that the power of ten (e.g., 2.5×10 −02 ) is expressed using E (e.g., 2.5E −02 ).  FIG. 4  is a cross-sectional view of a lens of Example 1. In  FIG. 1 , L 1  indicates the first lens, L 2  the second lens, L 3  the third lens, L 4  the fourth lens, L 5  the fifth lens, S the aperture diaphragm, and I the imaging surface.  FIG. 15( a )  is a spherical aberration diagram of the Example 1,  FIG. 15( b )  is an astigmatic aberration diagram, and  FIG. 15( c )  is a distortion aberration diagram.  FIG. 16  is a meridional comatic aberration diagram. Here, in the spherical aberration diagram, comatic aberration diagram and meridional comatic aberration diagram, g and d express the amount of spherical aberration along the g-line and the d-line, respectively. Additionally, in the astigmatic aberration diagram, the solid line S expresses the sagittal surface, and the dashed line M expresses the meridional surface, respectively (the same applies hereafter). 
         [0089]    The overall specifications of the imaging lens of the Example 1 are listed below:
   f=0.84 mm   fB=−0.04 mm   F=4   2Y=3 mm   ENTP=0.96 mm   EXTP=−2.17 mm   H1=1.47 mm   H2=−0.87 mm   
 
         [0098]    Surface data of the imaging lens of the Example 1 are listed below: 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                   
                   
                 effective 
               
               
                 surface number 
                 R (mm) 
                 D (mm) 
                 Nd 
                 vd 
                 radius (mm) 
               
               
                   
               
             
             
               
                  1 
                 ∞ 
                 0.00 
                   
                   
                 2.30 
               
               
                  2* 
                 38.031 
                 0.40 
                 1.58310 
                 59.5 
                 1.78 
               
               
                  3* 
                 0.682 
                 0.60 
                   
                   
                 0.98 
               
               
                  4* 
                 1.418 
                 0.90 
                 1.63470 
                 23.9 
                 0.87 
               
               
                  5* 
                 3.612 
                 0.19 
                   
                   
                 0.38 
               
               
                  6 (diaphragm) 
                 ∞ 
                 0.05 
                   
                   
                 0.18 
               
               
                  7* 
                 1.427 
                 0.74 
                 1.53048 
                 56.0 
                 0.31 
               
               
                  8* 
                 −0.376 
                 0.06 
                   
                   
                 0.51 
               
               
                  9* 
                 −0.789 
                 0.46 
                 1.63470 
                 23.9 
                 0.54 
               
               
                 10* 
                 9.008 
                 0.65 
                   
                   
                 0.88 
               
               
                 11 
                 ∞ 
                 0.41 
                 1.51630 
                 64.1 
                 1.36 
               
               
                 12 
                 −10.000 
                 0.05 
                 1.51400 
                 42.8 
                 1.48 
               
               
                 13 
                 −10.000 
               
               
                   
               
             
          
         
       
     
         [0099]    Aspheric coefficients of the Example  1  are listed below: 
       Second Surface 
       [0000]    
       
         K=−0.50000E+02, A4=0.91594E-01, A6=−0.43298E-01, A8=0.90611E-02, A10=−0.96295E-03, A12=0.53811E-04 
       
     
       Third Surface 
       [0000]    
       
         K=−0.10073E+01, A4=−0.42866E-01, A6=0.30980E+00, A8=0.33406E+00, A10=−0.11637E+01, A12=0.60040E+ 00   
       
     
       Fourth Surface 
       [0000]    
       
         K=−0.97639E+01, A4=0.22056E+00, A6=−0.39971E-01, A8=0.18526E+00, A10=−0.35313E+00, A12=0.19096E+00 
       
     
       Fifth Surface 
       [0000]    
       
         K=−0.46079E+01, A4=0.57221E+00, A6=0.13272E+01, A8=−0.81783E+01, A10=0.25511E+02, A12=−0.32938E+02 
       
     
       Seventh Surface 
       [0000]    
       
         K=−0.26660E+01, A4=0.75905E-01, A6=0.44468E+00, A8=0.26032E+01, A10=−0.38162E+02, A12=0.13486E+03 
       
     
       Eighth Surface 
       [0000]    
       
         K=−0.38839E+01, A4=−0.16438E+01, A6=0.39491E+01, A8=−0.13444E+02, A10=0.21046E+02, A12=0.23469E+01 
       
     
       Ninth Surface 
       [0106]    K=−0.20091E+02, A4=−0.16831E+00, A6=−0.40405E+01, A8=0.70058E+01, A10=−0.61198E+01, A12=−0.29349E+02 
       Tenth Surface 
       [0000]    
       
         K=−0.50000E+02, A4=−0.98947E-01, A6=−0.67924E-01, A8=−0.19606E+00, A10=0.31160E+00, A12=−0.13412E+00 
       
     
         [0108]    Single-lens data of the imaging lens of the Example 1 are listed below: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 lens 
                 initial surface 
                 focal length (mm) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 2 
                 −1.195 
               
               
                 2 
                 4 
                 3.175 
               
               
                 3 
                 7 
                 0.651 
               
               
                 4 
                 9 
                 −1.112 
               
               
                 5 
                 11 
                 19.296 
               
               
                   
               
             
          
         
       
     
       Example 2 
       [0109]    Lens data are listed in Table 2.  FIG. 17  is a cross-sectional view of a lens of Example 2. In  FIG. 17 , L 1  indicates the first lens, L 2  the second lens, L 3  the third lens, L 4  the fourth lens, S the aperture diaphragm, and I the imaging surface.  FIG. 18  (a) is a spherical aberration diagram of the Example 2,  FIG. 18 b   ) is an astigmatic aberration diagram, and  FIG. 18( c )  is a distortion aberration diagram.  FIG. 19  is a meridional comatic aberration diagram. 
         [0110]    The overall specifications of the imaging lens of the Example 2 are listed below:
   f=1.35 mm   fB=0 mm   F=2.82   2Y=3 mm   ENTP=0.96 mm   EXTP=−3.36 mm   H1=1.49 mm   H2=−0.89 mm   
 
         [0119]    Surface data of the imaging lens of the Example 2 are listed below: 
         [0000]    
       
         
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                   
                   
                   
                 effective 
               
               
                 surface number 
                 R (mm) 
                 D (mm) 
                 Nd 
                 vd 
                 radius (mm) 
               
               
                   
               
             
             
               
                  1 
                 ∞ 
                 0.00 
                   
                   
                 2.15 
               
               
                  2* 
                 2.811 
                 0.40 
                 1.54470 
                 56.2 
                 1.76 
               
               
                  3* 
                 0.428 
                 0.51 
                   
                   
                 0.92 
               
               
                  4* 
                 0.878 
                 0.87 
                 1.63470 
                 23.9 
                 0.83 
               
               
                  5* 
                 4.690 
                 0.14 
                   
                   
                 0.42 
               
               
                  6 (diaphragm) 
                 ∞ 
                 0.09 
                   
                   
                 0.24 
               
               
                  7* 
                 2.920 
                 0.73 
                 1.54470 
                 56.2 
                 0.38 
               
               
                  8* 
                 −0.778 
                 0.97 
                   
                   
                 0.63 
               
               
                  9* 
                 171.080 
                 0.46 
                 1.51630 
                 64.1 
                 1.50 
               
               
                 10 
                 −10.000 
                 0.03 
                 1.51400 
                 42.8 
                 1.50 
               
               
                 11 
                 −10.000 
               
               
                   
               
             
          
         
       
     
         [0120]    Aspheric coefficients of the Example 2 are listed below: 
       Second Surface 
       [0000]    
       
         K=−0.50000E+02, A4=0.80196E-03, A6=−0.26087E-02, A8=0.55773E-03, A10=−0.43133E-05 
       
     
       Third Surface  K=−0.82663E+00, A4=−0.51712E+00, A6=0.32110E+00, A8=−0.86436E+00, A10=0.10197E+00 
     Fourth Surface 
       [0000]    
       
         K=−0.25111E+01, A4=0.28043E+00, A6=−0.19015E+00, A8=0.16628E+00, A10=−0.12696E+00, A12=0.10060E-10 
       
     
       Fifth Surface 
       [0000]    
       
         K=0.21799E+02, A4=0.44802E+00, A6=−0.21419E+01, A8=0.30040E+02, A10=−0.94384E+02, A12=0.27246E-12 
       
     
       Seventh Surface 
       [0000]    
       
         K=−0.50000E+02, A4=0.43277E+00, A6=−0.96506E+00, A8=0.69548E+01, A10=−0.13672E+02, A12=0.10000E-11 
       
     
       Eighth Surface 
       [0000]    
       
         K=−0.10139E+01, A4=0.20724E+00, A6=0.97283E-02, A8=0.71893E+00, A10=−0.86320E-01, A12=0.50000E-11 
       
     
       Ninth Surface 
       [0000]    
       
         K=0.00000E+00, A4=0.11510E+00, A6=−0.10125E+00, A8=0.41053E-02, A10=0.85133E-02, A12=0.40119E-11 
       
     
         [0127]    Single-lens data of the imaging lens of the Example 2 are listed below: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 lens 
                 initial surface 
                 focal length (mm) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 2 
                 −0.987 
               
               
                 2 
                 4 
                 1.564 
               
               
                 3 
                 7 
                 1.213 
               
               
                 4 
                 10 
                 18.246 
               
               
                   
               
             
          
         
       
     
         [0128]    It is apparent, from the Examples and ideas described in the specification, to those skilled in the art that the present invention is not limited to the Examples described in the present specification, and includes other Examples or variations. 
         [0129]    The effects described in the present specification are merely illustrative and not limiting, and there may be other effects. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10 ,  10 A- 10 J imaging unit 
           11 ,  11 A,  11 B,  11 C,  11 G, and  11 H imaging element 
           11  a curved part 
           11   b  flat-plate part 
           11   c  imaging surface 
           11   d  pad 
           12 ,  12 D,  12 F,  12 G,  12 H,  12 J imaging lens 
           12   a  image-side optical surface 
           12   b  flange part 
           12   c  protrusion housing 
           14 ,  14 A,  14 B substrate 
           14   a  aperture 
           14   b  concave part 
           15  wire 
           16  combination holder 
           17  frame member 
           17   a  aperture 
           17   b  protrusion 
           18  micro lens 
           20  lens barrel 
           21  telephoto lens 
           22  annular coupling member 
           23  long lens barrel 
           24  camera body 
           25  wide-angle lens 
           26  short lens barrel 
           60  input key part 
           65  display part 
           70  touch panel 
           71  icon 
           80  wireless communication part 
           92  storage part 
           100  smart phone 
           101  control part