PATENT DOCUMENT

Publication Number: US-8639106-B1
Application Number: US-201213707463-A
Country: US
Kind Code: B1

Title: Magnetic add-on lenses with alignment ridge

Abstract:
A camera system includes a housing with an aperture and an alignment feature surrounding the aperture to define an optical axis extending through the aperture. A camera module is mounted inside the housing and engages the alignment feature to align the camera module with the optical axis. A lens assembly that may have a moveable element is included in the camera module. A voice coil motor may support the moveable element of the lens assembly. A plurality of magnets are arranged on the camera module adjacent to the alignment feature to retain a detachable lens on the housing and engage the alignment feature to align the detachable lens with the optical axis. The plurality of magnets may be further arranged to minimize interference with the voice coil motor and movement of the moveable element of the lens assembly.

Claims:
What is claimed is: 
     
       1. A camera system comprising:
 a housing having an aperture; 
 a camera module mounted inside the housing, the camera module including a lens assembly with an optical path that passes through the aperture; 
 an alignment feature that surrounds the aperture, aligns with an optical axis of the lens assembly of the camera module, and provides an engagement surface outside the housing to mechanically align a detachable lens with the optical axis of the lens assembly; and 
 a plurality of magnets mounted inside the housing adjacent to the engagement surface of the alignment feature to retain the detachable lens in alignment with the optical axis of the lens assembly. 
 
     
     
       2. The camera system of  claim 1  wherein:
 the lens assembly further includes at least one moveable element; 
 the camera module further includes a voice coil motor that moveably supports the at least one moveable element of the lens assembly; and 
 the plurality of magnets are coupled to the camera module and arranged to minimize interference with the voice coil motor and with movement of the at least one moveable element of the lens assembly. 
 
     
     
       3. The camera system of  claim 1  wherein the alignment feature aligns an optical axis of the detachable lens and the optical axis of the of the lens assembly each within 125×10 −6  meters (125 μm) (0.0005 inch) of the optical axis of the lens assembly as defined by the alignment feature. 
     
     
       4. The camera system of  claim 1  wherein the alignment feature aligns an optical axis of the detachable lens and the optical axis of the lens assembly each within a one degree angle from the optical axis of the lens assembly as defined by the alignment feature. 
     
     
       5. The camera system of  claim 1  further comprising the detachable lens and an additional lens coupled to the detachable lens such that either the detachable lens or the additional lens can selectably engage the alignment feature. 
     
     
       6. The camera system of  claim 5  further comprising an additional magnet mounted on the housing at a sufficient distance from the camera module to minimize interference with the voice coil motor, the additional magnet engaging the additional lens when the detachable lens engages the alignment feature. 
     
     
       7. The camera system of  claim 1  further comprising the detachable lens, wherein the detachable lens includes two optical elements that each bend the optical path at a right angle. 
     
     
       8. The camera system of  claim 1  further comprising the detachable lens, wherein the detachable lens includes a light pipe that directs light from a light source on the housing to a diffuser coupled to the detachable lens at an end furthest from the housing. 
     
     
       9. The camera system of  claim 1  wherein the alignment feature further comprise two or more electrically conductive segments coupled by electrically insulating segments. 
     
     
       10. The camera system of  claim 1  wherein the alignment feature is formed in a surface of the camera module. 
     
     
       11. The camera system of  claim 1  wherein the alignment feature is included in the housing and the camera module engages the alignment feature on the inside of the housing. 
     
     
       12. The camera system of  claim 1  further comprising the detachable lens, wherein the detachable lens includes:
 a first end; 
 a second end opposite the first end; 
 a second alignment feature at the second end of the detachable lens, the second alignment feature surrounding and aligning with an optical axis of the detachable lens, and providing a second engagement surface to mechanically align an optical axis of a second detachable lens with the optical axis of the detachable lens; and 
 a second magnet at the second end of the detachable lens, the second magnet to retain the second detachable lens in alignment with the optical axis of the detachable lens. 
 
     
     
       13. A detachable lens comprising:
 a surface on a first end of the detachable lens that engages an alignment feature to position an optical axis of the detachable lens within 125×10 −6  meters (125 μm) (0.0005 inch) of an optical axis defined by the alignment feature; and 
 a retainer that holds the detachable lens on a camera housing by magnetically engaging magnets that are on an opposite side of the camera housing from the surface that engages the alignment feature. 
 
     
     
       14. The detachable lens of  claim 13  wherein the alignment feature aligns the detachable lens with less than a 1 degree angle between the optical axis of the detachable lens and the optical axis defined by the alignment feature. 
     
     
       15. The detachable lens of  claim 13  further comprising an additional lens coupled to the detachable lens such that either the detachable lens or the additional lens can selectably engage the alignment feature. 
     
     
       16. The detachable lens of  claim 13  wherein the detachable lens includes two optical elements that each bend an optical path in the detachable lens at a right angle. 
     
     
       17. The detachable lens of  claim 13  wherein the detachable lens includes a light pipe that directs light from a light source on the housing to a diffuser coupled to the detachable lens at a second end opposite the first end. 
     
     
       18. The detachable lens of  claim 13  further comprising a second alignment feature and a magnet at a second end of the detachable lens opposite the first end, the second alignment feature arranged to be engaged by a second detachable lens as an alternative to the second detachable lens engaging the alignment feature. 
     
     
       19. A camera module comprising:
 an enclosure having a surface that engages an alignment feature included in a housing that contains the camera module to position an optical axis of the camera module within 125×10 −6  meters (125 μm) (0.0005 inch) of an optical axis defined by the alignment feature; 
 a lens assembly including at least one moveable element; 
 a voice coil motor coupled to the enclosure and moveably supporting the at least one moveable element of the lens assembly; and 
 a plurality of magnets attached to the enclosure adjacent to the alignment feature and arranged to minimize interference with the voice coil motor and with movement of the at least one moveable element of the lens assembly, and to provide a magnetic attachment for a detachable lens that engages the alignment feature on an opposite side of the housing from the camera module. 
 
     
     
       20. The camera module of  claim 19  wherein the alignment feature aligns the camera module with less than a one degree angle between the optical axis of the camera module and the optical axis defined by the alignment feature. 
     
     
       21. A camera module comprising:
 an enclosure that provides an alignment feature that extends through a housing, which contains the camera module, and that defines an optical axis of the camera module; 
 a lens assembly including at least one moveable element; 
 a voice coil motor coupled to the enclosure and moveably supporting the at least one moveable element of the lens assembly; and 
 a plurality of magnets attached to the enclosure adjacent to the alignment feature and arranged to minimize interference with the voice coil motor and with movement of the at least one moveable element of the lens assembly and to provide a magnetic attachment for a detachable lens that engages the alignment feature on an opposite side of the housing from the camera module. 
 
     
     
       22. The camera module of  claim 21  wherein the alignment feature aligns the camera module with less than a 1 degree angle between the optical axis of the camera module and the optical axis of the camera module defined by the alignment feature.

Description:
BACKGROUND 
     1. Field 
     Embodiments of the invention relate to the field of camera lenses; and more specifically, to lens mounts for securing an additional lens in the photographic light path. 
     2. Background 
     Cameras are being added to multi-function devices such as computers and mobile telephones that do not provide the structures found in conventional cameras that provide only an image capture function. Multi-function devices are often thin, offering little room for the optical elements of the camera portion of the device. This has led to the development of extremely compact camera modules that provide increasingly sophisticated image capturing in a very small device. In turn, the availability of these small camera modules has resulted in the production of extremely compact and thin single function cameras that also lack the structures found in conventional cameras. 
     Regardless of the amount of miniaturization of these camera modules, there is a limit to the types of optics that can be provided in the space available in a multi-function device or ultra-compact camera. The optics for providing a telephoto lens and other specialty lenses require a certain length for their optical path, which often is unavailable within a small device. Further, users generally want to use a specialty lens intermittently. Therefore it is desirable to be able to change the lenses that are in the optical path to provide specialty optics when desired. 
     It is possible to provide an additional lens, which may be an assembly including multiple lens elements, that works in conjunction with a lens provided by a camera module to provide specialty lens functions. When an additional lens is placed in the photographic light path, it is important that the additional lens be aligned with the optical axis of the lens provided by a camera module to provide good image quality. Existing compact devices that use compact camera modules generally do not provide the types of lens mounting structures found in conventional cameras due to space constraints. This makes it difficult to retain an additional lens and align it correctly with a compact camera module on a compact device. 
     It would be desirable to provide a lens mount for an additional lens that works in conjunction with a lens provided by a camera module on a compact device. 
     SUMMARY 
     A camera system includes a housing with an aperture and an alignment feature surrounding the aperture to define an optical axis extending through the aperture. A camera module is mounted inside the housing and engages the alignment feature to align the camera module with the optical axis. A lens assembly that may have a moveable element is included in the camera module. A voice coil motor may support the moveable element of the lens assembly. A plurality of magnets are arranged on the camera module adjacent to the alignment feature to retain a detachable lens on the housing and engage the alignment feature to align the detachable lens with the optical axis. The plurality of magnets may be further arranged to minimize interference with the voice coil motor and movement of the moveable element of the lens assembly. 
     Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by referring to the following description and accompanying drawings that are used to illustrate embodiments of the invention by way of example and not limitation. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals indicate similar elements. 
         FIG. 1  shows a portion of a compact device, such as a cellular telephone, that embodies the invention. 
         FIG. 2  shows a section view of the device taken along section line  2 - 2  in  FIG. 1 . 
         FIG. 3  shows an enlarged view of the camera module from  FIG. 2 . 
         FIG. 4  is an exploded view of a portion of a voice coil motor (VCM). 
         FIG. 5  is an assembled view of the portion of the VCM shown in  FIG. 4 . 
         FIG. 6  is a cross-section view of a detachable lens mounted outside the housing of the compact device. 
         FIG. 7  is a pictorial view of a camera system that includes one or more additional lenses coupled to a detachable lens. 
         FIG. 8  is a cross-section view of another detachable lens mounted outside the housing  108  of the compact device. 
         FIG. 9  shows a portion of another compact device, such as a cellular telephone, that embodies the invention. 
         FIG. 10  is a pictorial view of a camera system that includes a detachable lens that lies along the housing of the compact device. 
         FIG. 11  shows a section view of the detachable lens and the housing taken along section line  11 - 11  in  FIG. 10 . 
         FIG. 12  is a cross-section view of a first detachable lens mounted outside the housing of the compact device and a second detachable lens mounted to the first detachable lens. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Explanations that duplicate one another may have been omitted. 
     The meaning of specific terms or words used in the specification and claims should not be limited to the literal or commonly employed sense, but may be different and should be construed in the context of the specification. The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
       FIG. 1  shows a portion of a compact device  100 , such as a cellular telephone, that embodies the invention. The portion of the device  100  shown includes a camera system. Visible on the front of the device  100  are a lens portion  102  of a camera module, a lamp lens  104  for directing illumination to a photographic subject, and a microphone aperture  106  that may be used for admitting sound to be recorded in conjunction with image capture. In some embodiments the lamp and/or the microphone may not be present. 
       FIG. 2  shows a section view of the device  100  taken along section line  2 - 2  in  FIG. 1 .  FIG. 3  shows an enlarged view of the camera module  200  from  FIG. 2 . A lamp assembly  204  may be provided for illuminating a photographic subject through the lamp lens  104 . A microphone  206  may be in communication with the microphone aperture  106  to receive the admitted sound. 
     The housing  108  of the device  100  provides a protective enclosure for the components of the device including a camera system. The housing  108  has an aperture  202  that provides an opening in the housing. A camera module  200  is mounted inside the housing  108  with a light path  206  that passes through the aperture  202 . The camera module  200  includes a lens assembly  306 . 
     An alignment feature  208  surrounds the aperture  202 . The alignment feature  208  aligns with the lens assembly optics  308  of the camera module  200  to define an optical axis. The alignment feature  208  may be fixed within the aperture  202  in the housing  108  and engage a corresponding surface  210  on the camera module  200  to align the optics  308  of the camera module  200  with the optical axis of the alignment feature. In another embodiment, the alignment feature  208  may be fixed to the camera module  200  in alignment with the optics of the camera module. Both embodiments provide an engagement surface  110  outside the housing  108 . The exterior engagement surface  110  of the alignment feature  208  may engage a first end of a detachable lens mounted outside the housing to mechanically align the detachable lens with the optical axis of the optics of the camera module  200 . A number of magnets  310  are mounted inside the housing  108  adjacent to the engagement surface of the alignment feature  208  to retain the detachable lens in alignment with the optical axis. The magnets may be fastened to an inside surface of the housing  108  or to a surface of the camera module  200  that is adjacent the inside surface of the housing. 
     The alignment feature preferably aligns an optical axis of the detachable lens and an optical axis of the camera module each within about 125×10 −6  meters (125 μm) or about 0.0005 inch of the optical axis defined by the alignment feature. The alignment feature preferably aligns the optical axis of the detachable lens and the optical axis of the camera module each within about a one degree angle from the optical axis defined by the alignment feature. 
     The lens assembly  306  may include at least one moveable element  308 . The camera module  200  may include a voice coil motor  302 ,  304  that moveably supports the moveable element  308  of the lens assembly  306 . The magnets  310  provided to retain the detachable lens may be attached to the camera module  200  and arranged to minimize interference with the voice coil motor  302 ,  304  and movement of the moveable element  308  of the lens assembly  306 . 
       FIG. 4  is an exploded view of a portion of a voice coil motor (VCM).  FIG. 5  is an assembled view of the portion of the VCM shown in  FIG. 4 . The VCM includes a lens carrier  400  that supports a lens assembly, such as by a threaded engagement  406 . A wire coil  402  is wound around the exterior of the lens carrier  400 . The two ends  404  of the wire coil extend from the VCM to receive a controlled electrical current. A number of permanent magnet pole pieces  408  surround the wire coil  402  in the assembled VCM. A frame  410  may support the pole pieces  408  and provide a movable support for the lens carrier  400 . The permanent magnet pole pieces  408  are oriented as suggested by the arrows shown on the pole pieces to provide a magnetic field around the wire coil  402 . Energizing the wire coil  402  by supplying an electric current to the two ends  404  of the wire coil creates a magnetic field of a controlled strength that interacts with the magnetic field created by the permanent magnet pole pieces  408  to controllably move the lens carrier  400 . The movement of the lens assembly by the VCM may provide various optical functions such as autofocus, lens zoom, anti-shake, or a combination of such functions. 
     Additional permanent magnets  412  are provided adjacent to the engagement surface of the alignment feature  208  to retain a detachable lens in alignment with the optical axis. As suggested by the arrows on the permanent magnets  412 , the lens retaining magnets  412  may be oriented with their magnetic poles aligned substantially at right angles to the magnetic poles of the permanent magnet pole pieces  408 . It has been found that such a relationship between the lens retaining magnets  412  and the permanent magnet pole pieces  408  minimizes the interference of the lens retaining magnets on the function of the VCM. Conversely, it has been found that aligning the poles of the lens retaining magnets  412  and the permanent magnet pole pieces  408  to be substantially parallel, with either the same or opposing polarities, produces a significant interference of the lens retaining magnets with the function of the VCM when the magnets are as close to the VCM as required by a compact camera system. 
       FIG. 6  is a cross-section view of a detachable lens  600  mounted outside the housing  108  of the compact device. A first end  602  of the detachable lens  600  engages the exterior engagement surface  110  of the alignment feature  208  ( FIG. 3 ) to mechanically align the detachable lens with the optical axis of the optics of the camera module  200 . The detachable lens  600  includes a retainer  604  adjacent the first end  602  of the detachable lens that holds the detachable lens on the camera housing  108  by magnetically engaging the magnets  310  that are on an opposite side of the camera housing from the surface that engages the alignment feature. The retainer  604  may be a non-magnetic material that is attracted by the magnets  310  inside the camera housing. In another embodiment, the retainer  604  may be one or more magnets arranged to be attracted by the magnets  310  inside the camera housing. 
       FIG. 7  is a pictorial view of a camera system that includes one or more additional lenses  702 ,  704  coupled to a detachable lens  700  such that either the detachable lens or the additional lens can selectably engage the alignment feature. The camera system may include an additional magnet mounted on the housing  108  at a sufficient distance from the camera module to minimize interference with the voice coil motor and movement of the moveable element of the lens assembly. The additional magnet engages at least one of the additional lenses  702 ,  704  to stabilize the coupled lens assembly on the camera body when the detachable lens  200  engages the alignment feature. 
       FIG. 8  is a cross-section view of another detachable lens  800  mounted outside the housing  108  of the compact device. The detachable lens  800  includes a light pipe that directs light from a light source  104 ,  204  on the housing  108  to a diffuser  806  coupled to the detachable lens  800  at an end furthest from the housing and the light source  104 ,  204 . The light pipe may include a cylindrical reflector  802  that is coaxial with the optical elements  808  of the lens  800 . The cylindrical reflector  802  may cooperate with an external reflective surface  804  of a cylindrical mount that supports the optical elements  808  to reflect and disperse the light emitted by the lamp lens  104  on the housing  108  of the compact device to provide a reasonably uniform illumination of the diffuser  806 . The diffuser  806  illuminates a subject being photographed with a “ring light” that surrounds the lens. 
       FIG. 9  shows a portion of another compact device  900 , such as a cellular telephone, that embodies the invention. The portion of the device  900  shown includes a camera system. Visible on the front of the device  900  is a lens portion  902  of a camera module. An alignment feature  208  surrounds the aperture  202 . The alignment feature  208  aligns with the lens assembly optics  308  of the camera module  200  to define an optical axis. An alignment feature that includes an engagement surface  910 ,  912 ,  914 ,  916  surrounds the aperture  902 . The alignment feature aligns with the lens assembly optics of the camera module to define an optical axis as described above in connection with  FIGS. 1-3 . 
     The alignment feature is made from two or more electrically conductive segments  910 ,  912  coupled by electrically insulating segments  914 ,  916 . The electrically conductive segments  910 ,  912  may provide power and/or control signals to a detachable lens that engages the alignment feature. The electrically conductive segments  910 ,  912  may receive data and/or control signals from a detachable lens that engages the alignment feature. In some embodiments the electrically insulating segments  914 ,  916  may be of a size that creates a mechanical index to control the angular position of a detachable lens that engages the alignment feature. 
       FIG. 10  is a pictorial view of a camera system that includes a detachable lens  1000  that lies along the housing  908  of the compact device when the detachable lens engages the alignment feature of the camera module. This may be advantageous for lenses that require a long optical path and would otherwise project a substantial distance from the compact device. 
       FIG. 11  shows a section view of the detachable lens  1000  and the housing  908  taken along section line  11 - 11  in  FIG. 10 . The detachable lens  1000  includes two optical elements, such as mirrors  1110 ,  1120  that each bend the optical path at a right angle. This allows the optical elements, such as one or more lenses  1114 ,  1116 ,  1118 , to be placed on an optical path that is at right angles to the optical patch of the camera module and parallel to a face of the housing. The mirror  1120  or other optical element that bends the optical path at a right angle furthest from the camera module redirects the optical path to be parallel to the optical path of the camera module allowing light from the scene being photographed to enter the detachable lens  1000  through a forward facing aperture  1002 . 
     The camera system may include an additional magnet  1108  mounted on the housing  908  at a sufficient distance from the camera module to minimize interference with the voice coil motor and movement of the moveable element of the lens assembly. The additional magnet  1108  may engage another magnet  1106  or magnetic catch in the detachable lens  1000  to stabilize the detachable lens on the camera body when the detachable lens engages the alignment feature. 
       FIG. 12  is a cross-section view of another detachable lens  1200  mounted outside the housing  108  of the compact device. A first end  1202  of the first detachable lens  1200  engages the exterior engagement surface  110  of the alignment feature  208  ( FIG. 3 ) to mechanically align the first detachable lens with the optical axis of the optics of the camera module  200 . The first detachable lens  1200  includes a retainer  1204  adjacent the first end  1202  of the detachable lens that holds the first detachable lens on the camera housing  108  by magnetically engaging the magnets  310  that are on an opposite side of the camera housing from the surface that engages the alignment feature. The retainer  1204  may be a non-magnetic material that is attracted by the magnets  310  inside the camera housing. In another embodiment, the retainer  1204  may be one or more magnets arranged to be attracted by the magnets  310  inside the camera housing. 
     The first detachable lens  1200  includes a second alignment feature  1210  and a second magnet  1208  at a second end of the first detachable lens opposite the first end  1202 . The second alignment feature surrounds and aligns with an optical axis of the first detachable lens. The second alignment feature provides an engagement surface to mechanically align an optical axis of the second detachable lens  1220  with the optical axis of the first detachable lens. The first detachable lens  1200  further includes a second magnet  1208  at a second end of the first detachable lens opposite the first end  1202 . The second magnet  1208  retains the second detachable lens  1220  with the optical axis of the second detachable lens in alignment with the optical axis of the first detachable lens. 
     In the embodiment illustrated, the second alignment feature  1210  is arranged to be engaged by the second detachable lens  1220  as an alternative to the second detachable lens engaging the alignment feature  208  of the compact device. In other embodiments (not illustrated) the second alignment feature is arranged to be engaged by a second detachable lens that is not capable of engaging the alignment feature of the compact device. 
     While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20121206
Publication Date: 20140128
Grant Date: 20140128
Priority Date: 20121206
Inventors: GLEASON JEFFREY NATHAN
SCEPANOVIC MISHA
Assignee: APPLE INC
CPC Classifications: [{"code": "G03B17/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03B17/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03B3/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B17/565", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B2205/0007", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B2205/0046", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B2205/0069", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B15/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B15/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B3/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B17/565", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B2205/0007", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B2205/0069", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B2205/0046", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B15/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B7/08", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49957995