Patent Publication Number: US-2022239816-A1

Title: Integrated image sensor and lens assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. patent application Ser. No. 16/735,183, filed on Jan. 6, 2020, which is a continuation of U.S. patent application Ser. No. 16/144,140, filed on Sep. 27, 2018, now U.S. Pat. No. 10,530,978, which is a continuation of U.S. patent application Ser. No. 14/705,891, filed on May 6, 2015, now U.S. Pat. No. 10,122,902, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/019,146, filed Jun. 30, 2014, and U.S. Provisional Patent Application Ser. No. 61/990,053, filed May 7, 2014. The subject matter of each of the above-identified applications is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Manufacturing of lens assemblies for high-resolution cameras typically require a high degree of precision in positioning components of the lens assembly to ensure that the lens will achieve proper focus. As a result, a challenge exists in achieving a fast, automated, and high-yielding assembly process for high-resolution cameras. 
     In a conventional manufacturing process, a lens barrel housing the camera lens is placed within a housing assembly affixed to an image sensor. Upon testing the lens barrel to position it for proper alignment, the lens barrel is affixed to the housing assembly using a “floating” assembly process whereby the lens barrel is attached to the housing using adhesive between a ridge of the lens barrel extending parallel to the image plane and an inner lip of the housing extending parallel to the image plane. The adhesive may expand and/or contract when cured, or after curing, the adhesive may expand and/or contract over time based on changes in temperature or other conditions. Because the adhesive is placed between surfaces of the lens barrel and housing that are parallel to the image plane, the expansion or contraction of the adhesive causes the lens to shift along the optical axis, thus altering the distance between the lens and the image sensor. This affects focus of the lenses and compromises performance and yield. 
    
    
     
       DETAILED DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exploded view of an example integrated image sensor and lens assembly, according to one embodiment. 
         FIG. 2  illustrates a cross-sectional view of the lens holder and lens barrel sliced along a plane parallel to the optical axis, according to one embodiment. 
         FIG. 3  illustrates a cross-sectional view of the lens holder and lens barrel sliced along a plane parallel to the optical axis, according to one embodiment. 
         FIG. 4  illustrates a cross-sectional view of the lens holder and lens barrel sliced along a plane parallel to the optical axis, according to one embodiment. 
         FIG. 5  illustrates an example integrated sensor and lens assembly undergoing a curing process during manufacture, according to an embodiment. 
         FIG. 6  is an enlarged view of the example integrated sensor and lens assembly undergoing the curing process during manufacture as illustrated in  FIG. 5 . 
         FIG. 7  illustrates an example integrated sensor and lens assembly in an example camera body, according to one embodiment. 
         FIG. 8  illustrates an example camera that includes the example integrated image sensor and lens assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The figures and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed. 
     Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the disclosed system (or method) for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. 
     Configuration Overview 
     In an embodiment, an integrated image sensor and lens assembly comprises a lens barrel adhered to a lens holder using an adhesive ring applied between an exterior surface of the lens barrel and an interior surface of the lens holder that are oriented in a direction perpendicular to the image plane (parallel to the optical axis). The lens barrel and lens holder are bonded based on the sheer strength (rather than the tensile strength) of the adhesive. Thus, adhesive expansion does not substantially affect the distance between the lens and the image sensor and therefore does not affect the focal plane of the assembly. As described herein, substantially constant refers to the optical distance is within a predefined tolerance that would be acceptable to those skilled in art. In various embodiments, the predefined tolerance can be, for example, a 1% tolerance, a 2% tolerance, a 5% tolerance, etc. While expansion or contraction of the adhesive may still occur, the forces are directed radially (rather than axially) and are counteracted because the adhesive is applied concentrically. 
     In another embodiment, an integrated image sensor and lens assembly comprises a lens barrel adhered to an image sensor assembly using an adhesive applied between a surface of the lens barrel and an outer side wall of the image sensor assembly that are oriented in a direction perpendicular to the image plane (parallel to the optical axis). The lens barrel and image sensor assembly are bonded based on the sheer strength (rather than the tensile strength) of the adhesive. Thus, adhesive expansion does not substantially affect the distance between the lens and the image sensor and therefore does not affect the focal plane of the assembly. While expansion or contraction of the adhesive may still occur, the forces are directed radially (rather than axially) and are counteracted because the adhesive is applied concentrically. 
       FIG. 1  illustrates an exploded view of an embodiment of an integrated image sensor and lens assembly  100 . The integrated image sensor and lens assembly  100  comprises an image sensor substrate  140 , an image sensor assembly  130 , a lens holder  120 , and a lens barrel  110 . The image sensor substrate  140  comprises a printed circuit board for mounting the image sensor assembly  130  and may furthermore include various electronic components that that operate with the image sensor assembly  130  or provide external connections to other components of the camera system. The image sensor assembly  130  houses an image sensor (e.g., a high-definition image sensor) for capturing images and/or video and includes structural elements for physically coupling the image sensor assembly  130  to the image sensor substrate  140  and to the lens holder  120 . The image sensor of the image sensor assembly  130  lies on an image plane  160 . The lens holder  120  physically couples with the image sensor assembly  130  and the lens barrel  110 . In one embodiment, the lens holder  120  comprises a base portion  124  and a tube portion  122 . The base portion  124  includes a bottom surface in a plane substantially parallel to a surface of the image sensor substrate  140 . Furthermore, the base portion  124  includes a recess (not viewable in  FIG. 1 ) to enable the bottom surface of the base portion  124  to lie flat against the image sensor substrate  140  while partially enclosing the image sensor assembly  130 . The tube portion  122  of the lens holder  120  extends away from the image sensor assembly  130  along the optical axis  150  and includes a substantially cylindrical channel for receiving the lens barrel  110 . The lens barrel  110  comprises one or more lenses or other optical components to direct light to the image sensor assembly  130 . The lens barrel  110  comprises a lower portion  116 , one or more barrel arms  114 , and a lens window  112 . The lower portion of the lens barrel  116  is substantially cylindrical and structured to at least partially extend into the channel of the tube portion  122  of the lens holder  120 . The lens arms  114  extend radially from the body of the lens barrel  110  and are outside the channel of the lens holder  120  when assembled. The lens arms  114  may be used to physically couple the lens barrel  110  to the camera body (not shown). The lens window  112  includes optical components to enable external light to enter the lens barrel  110  and be directed to the image sensor assembly  130 . 
       FIG. 2  illustrates a cross-sectional view of the lens holder  120  and lens barrel  110  sliced along a plane parallel to the optical axis  150 . Interior components (e.g., lenses) of the lens barrel  110  are omitted to more clearly show the structural features of the lens barrel  110 . As illustrated in  FIG. 2 , the lower portion  116  of the lens barrel  110  partially extends into the tube portion  122  of the lens holder  120 . An adhesive  234  is applied between an interior surface of the tube portion  122  that is oriented parallel to the optical axis  150  and an exterior surface of the lower portion  116  of the lens barrel  110  (also oriented parallel to the optical axis  150 ) to radially bond the lens barrel  110  to the lens holder  120 . The section of the lower portion  16  of the lens barrel  110  that extends into the tube portion  122  of the lens holder  120  is adhered to the tube portion  122  via the adhesive  234 . The lens barrel  110  and lens holder  120  are bonded based on the sheer strength of the adhesive  234 . If expansion of the adhesive  234  occurs, the forces will be directed radially (i.e., along a plane parallel to the image plane) and will therefore not substantially affect the distance between the lens of the lens barrel  110  and the image plane  160 . 
     In the illustrated embodiment, the lower portion  16  of the lens barrel  110  includes a plurality of ridges  236  on the exterior surface. The ridges  236  increase the surface area on the exterior surface of the lower portion  116  for the adhesive  234  to bond to and thereby increase the adhesive strength. 
     The illustrated embodiment also shows a gasket  232  positioned at a lower end of the lens barrel  110  just below the adhesive  234 . The gasket  232  may be used in the manufacturing process as a barrier to prevent the adhesive  234  from overflowing and potentially reaching the image sensor if the adhesive  234  is insufficiently viscous. In one embodiment, the gasket  232  comprises a pliable material (e.g., rubber, plastic, etc.) so that it does not prevent fine adjustments from being made to the positioning of the lens barrel  110  relative to the image sensor assembly  130  along the optical axis during the assembly and alignment process. The pliability of the gasket  232  furthermore absorbs any forces along the optical axis caused by expansion or contraction of the adhesive  234 . 
       FIG. 3  illustrates a cross-sectional view of the lens holder  120  and lens barrel  110  sliced along a plane parallel to the optical axis  150 . In the illustrated example, the interior surface of the lens barrel  110  is substantially smooth and the adhesive  234  is applied to the interior surface of the lens barrel  110 . 
       FIG. 4  illustrates a cross-sectional view of the lens holder  120  and lens barrel  110  sliced along a plane parallel to the optical axis  150 . The gasket  232  is omitted in this illustrated embodiment. 
       FIG. 5  illustrates an embodiment of an integrated sensor and lens assembly undergoing a curing process during manufacture. In the illustrated embodiment, the lens holder  110  includes one or more ports  506  that enable ultraviolet (UV) rays to pass through from the LED UV system  504 . The UV rays cure the adhesive  234  and thereby to lock the lens barrel  110  and lens holder  120  in place after tested and properly aligned. A top ring UV cure  502  is also applied to the top of the lens holder  110 . In one embodiment, the lens holder  120  includes four ports  506  equally spaced around the circumference of the tube portion  122  of the lens holder  110 . Alternatively, three equally spaced ports  506  or a different number or configuration of ports  506  may be used. 
     The curing process settles the lens barrel  110  in the lens holder to provide the desired modulation transfer function (MTF) and focuses position of the lenses prior to further thermal curing. As illustrated in  FIG. 6 , the adhesive has a curing depth such that it immobilizes the settled lens barrel  110  prior to thermal curing. Particularly, the depth of the adhesive from the external opening of the pot  506  to the interior surface of the lens barrel  110  (for example, the depth  610  in  FIG. 6 ) locks the lens barrel  110  in place even before curing is applied. 
       FIG. 7  illustrates another alternative embodiment of an integrated sensor and lens assembly  702  for use in a camera body  700 . The lens assembly  702  comprises a lens barrel  110 , an image sensor substrate  140 , and an image sensor assembly  130 . Similar to the embodiment illustrated in  FIG. 1 , the image sensor substrate  140  comprises a printed circuit board for mounting the image sensor assembly  130  and may furthermore include various electronic components that that operate with the image sensor assembly  130  or provide external connections to other components of the camera system. The image sensor assembly  130  houses an image sensor (e.g., a high-definition image sensor) for capturing images and/or video and includes structural elements for physically coupling the image sensor assembly  130  to the image sensor substrate  140  and to lens barrel  110 . The image sensor of the image sensor assembly  130  lies on an image plane  160 . 
     The lens barrel  110  comprises one or more lenses or other optical components to direct light to the image sensor assembly  130 . The lens barrel  110  comprises a lower portion  116  and an upper portion  704  having a lens window  112 . The lower portion of the lens barrel  116  includes a channel  706  for receiving the image sensor assembly  130 . The channel  706  can be substantially cylindrical, square, rectangular, or other shaped. The lens barrel  110  may be physically coupled to the camera body  700 . The lens window  112  includes optical components to enable external light to enter the lens barrel  110  and be directed to the image sensor assembly  130 . The lens barrel  110  is positioned such that the image sensor assembly  130  protrudes into the channel  706 . An interior surface of the lens barrel  110  is oriented to be substantially perpendicular to the image plane  160  and substantially parallel to the optical axis  150 . 
     The image sensor assembly  130  is adhered to the interior surface of the lens barrel  110  directly via the adhesive  234 , without a separate lens holder. The image sensor assembly  130  includes a plurality of side walls oriented in a direction substantially perpendicular to the substrate  140 . The adhesive  234  is applied between the interior surface of the lens barrel  110  and an outer side wall of the image sensor  130 . The integrated sensor and lens assembly  702  is substantially cylindrical, square, or rectangular. 
     In one embodiment, the channel  706  of the lens barrel  110  is substantially square or rectangular and the image sensor assembly  130  is substantially square or rectangular. The channel  706  of the lens barrel  110  mates with the image sensor assembly  130  such that an interior surface of the channel  706  of the lens assembly  1302  adheres to the outer side wall of the image sensor  130 . In another embodiment, the channel  706  of the lens barrel  110  may be substantially circular and mate with a substantially circular image sensor  130 . In yet another embodiment (not shown), an adhesive  234  is applied between a top surface of the image sensor assembly  130  and a shelf that protrudes from an interior surface of the lens barrel  112  in a direction substantially parallel to the top surface of the image sensor  130 . Other embodiments and features described above (e.g., the use of gasket  232 , the use of ridges  236 ) may be combined with the embodiment of  FIG. 13  in which the lens assembly  702  includes a lens barrel adhered to the image sensor assembly  130  via the adhesive  234  directly. The gasket may be positioned at a lower end of the lens barrel  110  just below the adhesive  234 . 
     Example Camera System Configuration 
       FIG. 8  illustrates an embodiment of an example camera  800  that includes the integrated image sensor and lens assembly  100  described above. The camera  800  comprises a camera body having a camera lens structured on a front surface of the camera body, various indicators on the front of the surface of the camera body (such as LEDs, displays, and the like), various input mechanisms (such as buttons, switches, and touch-screen mechanisms), and electronics (e.g., imaging electronics, power electronics, etc.) internal to the camera body for capturing images via the camera lens and/or performing other functions. The camera I  800  is configured to capture images and video, and to store captured images and video for subsequent display or playback. As illustrated, the camera  800  includes a lens  802  configured to receive light incident upon the lens and to direct received light onto an image sensor internal to the lens. The lens  802  is enclosed by a lens ring  804 , which are both part of the integrated image sensor and lens assembly  100  discussed above. 
     The camera  800  can include various indicators, including the LED lights  806  and the LED display  808 . The camera  800  can also include buttons  810  configured to allow a user of the camera to interact with the camera, to turn the camera on, and to otherwise configure the operating mode of the camera. The camera  800  can also include a microphone  812  configured to receive and record audio signals in conjunction with recording video. The side of the camera  800  includes an I/O interface  814 . 
     Additional Configuration Considerations 
     Throughout this specification, some embodiments have used the expression “coupled” along with its derivatives. The term “coupled” as used herein is not necessarily limited to two or more elements being in direct physical or electrical contact. Rather, the term “coupled” may also encompass two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other, or are structured to provide a thermal conduction path between the elements. 
     Likewise, as used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. 
     In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. 
     Finally, as used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for a camera expansion module as disclosed from the principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.