Abstract:
An improved lens mount and related lens and lens barrel positioning methods are provided. In one example, a lens mount for use with a miniature camera can include a ring member having a substantially cylindrical interior surface defining a substantially cylindrical interior space. A plurality of elongate ribs are disposed on the interior surface of the ring member and are adapted to exert pressure against an external surface of a lens barrel received by the ring member. In another example, a method of positioning a lens barrel includes inserting a lens barrel into a ring member having a substantially cylindrical interior surface. Pressure can be exerted against an external surface of the lens barrel from a plurality of elongate ribs disposed on the interior surface of the ring member. The pressure can prevent rotation of the lens barrel along at least three axes of rotational freedom.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 11/511,001 filed on Aug. 28, 2006 now U.S. Pat. No. 7,359,131 entitled “Lens Positioning Systems and Methods”, which is a continuation application of U.S. patent application Ser. No. 11/487,908 filed on Jul. 17, 2006 entitled “Lens Positioning Systems and Methods”, now abandoned, which is a continuation-in-part application of U.S. patent application Ser. No. 11/361,608 filed on Feb. 24, 2006 entitled “Autofocus Camera”, which claims the benefit of U.S. Provisional Patent Application No. 60/657,261 filed on Feb. 28, 2005 entitled “Autofocus Camera”, all of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention generally relates to optics and, more particularly, to the alignment of lenses that are suitable for use with miniature cameras. 
     2. Related Art 
     Digital cameras typically use one or more lenses to provide focused or zoomed images to an imager. In order for the imager to obtain accurate images, it is important that the lenses be properly aligned with the imager. In particular, if lenses are skewed in one or more degrees of rotational freedom or translational freedom, light may not be properly focused on the imager. This can result in images appearing off centered or distorted on the imager. 
     Manufacturers frequently rely on camera components to be manufactured within sufficiently small tolerances (for example, within approximately 0.025 mm) such that when the components are assembled, lenses are sufficiently aligned to provide satisfactory image quality on an imager. Unfortunately, optical components may not always be available within particular desired tolerances. The accumulation of variations in optical component characteristics, dimensions, and tolerances can result in misalignment of lenses. 
     In addition, even when lenses are initially properly aligned with an imager, they may become misaligned as a result of impacts received by the digital camera. As a result, relying on manufacturing tolerances and accurate assembly alone can still lead to misalignment of lenses over time. Also, miniature cameras are generally unable to provide meaningful image stabilization. For example, if lenses experience lateral movement in relation to the imager, conventional miniature cameras typically cannot re-align the lenses in relation to the imager to compensate for such anomalies. 
     Accordingly, there is a need for an improved approach to lens alignment that overcomes the deficiencies in prior approaches as discussed above. In particular, there is a need to provide an improved lens alignment approach that provides for reliable alignment of one or more lenses when employed in personal electronic devices such as miniature digital cameras. 
     SUMMARY 
     In accordance with one embodiment of the present invention, a lens mount for use with a miniature camera includes: a ring member having a substantially cylindrical interior surface defining a substantially cylindrical interior space; and a plurality of elongate ribs disposed on the interior surface of the ring member, wherein the ribs are adapted to exert pressure against an external surface of a lens barrel received by the ring member. 
     In accordance with another embodiment of the present invention, a lens mount for use with a miniature camera, includes: a ring member; a base member; a plurality of flexure members attaching the ring member with the base member; and a plurality of tension members associated with the flexure members, wherein each tension member is adapted to exert force on at least one of the flexure members, wherein the at least one of the flexure members is adapted to bend in response to the force, and wherein the ring member is adapted to move in response to the bending of the at least one of the flexure members. 
     In accordance with another embodiment of the present invention, a lens mount for use with a miniature camera includes: a ring member; a base member flexibly connected with the ring member; and a first actuator assembly connected with a first side of the ring member and adapted to move the ring member in a first plurality of directions relative to the base member. 
     In accordance with another embodiment of the present invention, a method of positioning a lens barrel, includes: inserting a lens barrel into a ring member having a substantially cylindrical interior surface; and exerting pressure against an external surface of the lens barrel from a plurality of elongate ribs disposed on the interior surface of the ring member, wherein the pressure prevents rotation of the lens barrel along at least three axes of rotational freedom. 
     In accordance with another embodiment of the present invention, a method of positioning a lens includes: providing a lens mount comprising: a ring member, a base member, and a first flexure member attaching the ring member with the base member; providing a lens held by the ring member; applying force to the first flexure member; permitting the first flexure member to bend in response to the force applied to the first flexure member; and permitting the ring member to move in response to the bending of the first flexure member. 
     In accordance with another embodiment of the present invention, a method of positioning a lens includes: providing a lens mount comprising: a ring member, a base member flexibly connected with the ring member, and a first actuator assembly connected with a first side of the ring member; providing a lens held by the ring member; and operating the first actuator assembly to move the ring member in a first direction relative to the base member. 
     The scope of the invention is defined by the claims, which are incorporated into this section by reference. A more complete understanding of embodiments of the present invention will be afforded to those skilled in the art, as well as a realization of additional advantages thereof, by a consideration of the following detailed description of one or more embodiments. Reference will be made to the appended sheets of drawings that will first be described briefly. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates a front view of a lens mount having a plurality of ribs in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates a perspective view of the lens mount of  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  illustrates a front view of another lens mount having a plurality of ribs in accordance with an embodiment of the present invention. 
         FIG. 4  illustrates a perspective view of the lens mount of  FIG. 3  in accordance with an embodiment of the present invention. 
         FIG. 5  illustrates a front view of a lens mount having a plurality of flexure members in accordance with an embodiment of the present invention. 
         FIG. 6  illustrates a front view of a lens mount having a plurality of actuator assemblies in accordance with an embodiment of the present invention. 
         FIG. 7  illustrates a personal electronic device incorporating a lens mount in accordance with an embodiment of the present invention. 
     
    
    
     Like element numbers in different figures represent the same or similar elements. 
     DETAILED DESCRIPTION 
     Referring now to the drawings wherein the showings are for purposes of illustrating embodiments of the present invention only, and not for purposes of limiting the same,  FIGS. 1 and 2  illustrate front and perspective views, respectively, of a lens mount  100  having a plurality of ribs  130  in accordance with an embodiment of the present invention. Lens mount  100  includes a ring member  110  connected with a base member  160 . A substantially cylindrical interior surface  180  of lens mount  100  defines a substantially cylindrical interior space  120 . Ribs  130  are disposed on interior surface  180  and can exhibit substantially hemispherical surfaces facing toward interior space  120 . 
     As illustrated in  FIG. 1 , a lens barrel  170  can be inserted into ring member  110 . For example, in one embodiment, threads (not shown) can be provided on an external surface of lens barrel  170  for engaging threads (not shown) on interior surface  180 . As a result, lens barrel  170  may be screwed into ring member  110  In  FIG. 2 , lens mount  100  is illustrated without lens barrel  170  in order to more fully show interior space  120 , interior surface  180 , and ribs  130 . 
     Ribs  130  can be implemented in various configurations as may be desired for particular applications. For example, in one embodiment, ribs  130  may be implemented as being substantially parallel with each other. In another embodiment, ribs  130  may be substantially aligned along a length of interior surface  180 . In yet another embodiment, ribs  130  may be approximately equally spaced about a perimeter of interior surface  180 . It will also be appreciated that any desired number of ribs  130  may be used. 
       FIGS. 3 and 4  illustrate front and perspective views, respectively, of another lens mount  200  having a plurality of ribs  150  in accordance with an embodiment of the present invention. It will be appreciated that lens mount  200  can be implemented in the manner of lens mount  100 , with modifications made to ribs  130 . In particular, ribs  130  have been replaced by ribs  150  which exhibit substantially flat surfaces facing toward interior space  120 . 
     Ring members  110 / 210  and ribs  130 / 150  can be sized such that ribs  130 / 150  contact and exert pressure against an external surface of lens barrel  170  while it is inserted into ring members  110 / 210 . As a result of the pressure between ribs  130 / 150  and lens barrel  170 , lens barrel  170  can be prevented from rotating along at least three axes of rotational freedom: X axis (pitch), Y axis (yaw), and Z axis (roll) which are illustrated in  FIGS. 1 and 2 . This pressure can permit lens barrel  170  to remain securely held by ring members  110 / 210 , despite possible imperfections in the diameters of lens barrel  170  or ring members  110 / 210 . 
     As a result, it will be appreciated that lens mounts  100  and  200  can be used to align a lens, such as a lens of a digital camera provided alone or in lens barrel  170 . For example, a lens or lens barrel  170  can be inserted into interior space  120  of ring member  110 . Pressure can then be exerted against the external surface of the lens or lens barrel  170  from ribs  130 / 150 . As a result of this pressure, rotation of lens barrel  170  along at least three axes of rotational freedom can be minimized. In one embodiment, the inserting operation can include screwing lens barrel  170  into ring member  110  or  210  by engaging threads (not shown) of lens barrel  170  with threads (not shown) of ring member  110  or  210 . 
       FIG. 5  illustrates a front view of a lens mount  300  having a plurality of flexure members  330 A/B in accordance with an embodiment of the present invention. Lens mount  300  includes a ring member  310 , a base member  360 , flexure members  330 A/B, and a plurality of tension members  340 A/B. 
     Ring member  310  is attached with base member  360  by flexure members  330 A/B. As a result, ring member  310  can be suspended and supported above base member  360  by flexure members  330 A/B. A lens or lens barrel, such as lens barrel  170  of  FIGS. 1 and 3  can be inserted into an interior space  320  of ring member  310 . The lens or lens barrel can be secured with ring member  310  using threads and/or other appropriate engagement members. 
     Flexure members  330 A/B can be implemented to be flexible and bendable in response to force exerted upon them by tension members  340 A/B. In one embodiment, flexure members  330 A/B may be comprised of silicon. Tension members  340 A/B are associated with flexure members  330 A/B and, in one embodiment, tension members  340 A/B and flexure members  330 A/B can have a one-to-one correspondence with each other. In the embodiment illustrated in  FIG. 5 , tension members  340 A/B are implemented as screws which may be screwed into base member  360  through appropriate apertures  345 A/B in base member  360  for receiving tension members  340 A/B. However, it will be appreciated that tension members  340 A/B may alternatively be implemented as actuators, micro-electro-mechanical systems (MEMS) devices, or any other appropriate components suitable for exerting force on one or more of flexure members  330 A/B. In one embodiment, flexure member  330 A and tension member  340 A may comprise a first MEMS device, and flexure member  330 B and tension member  340 B may comprise a second MEMS device. In such an embodiment, flexure members  330 A/B may optionally be comprised of silicon. 
     Force can be applied to one or more of flexure members  330 A/B by one or more of tension members  340 A/B. For example, force can be applied by left tension member  340 A to left flexure member  330 A in the direction of arrow  350  by screwing left tension member  340 A into base  360 . As a result of the force applied by left tension member  340 A, left flexure member  330 A can be permitted to bend to a deformed position  380 . In response to the bending of left flexure member  330 A, ring member  310  can be permitted to move in an arc in the direction of arrow  370  to a translated position  390 . It will be appreciated that the operations mirroring those described with reference to left flexure member  330 A and left tension member  340 A can be performed using right flexure member  330 B and right tension member  340 B. 
     It will be appreciated that by applying various amounts of force to one or more of flexure members  330 A/B through one or more of tension members  340 A/B, ring member  310  can be translated in a plurality of directions. For example, by selectively applying force from left tension member  340 A or right tension member  340 B, ring member  310  can be made to rotate along at least one axis of rotational freedom in the directions of arrows  355 . It will be appreciated when ring member  310  is moved in the directions of arrows  355 , it can be moved along at least two axes of translational freedom (i.e., along both the X and Y axes denoted in  FIG. 5 ). Moreover, by applying approximately equal force by tension members  340 A/B, ring member  310  can be moved up and down in directions corresponding to one axis of translational freedom (i.e., along the Y axis denoted in  FIG. 5 ). 
     By moving ring member  310  in relation to the various degrees of freedom as discussed above, the lens or lens barrel secured by ring member  310  can be adjusted in relation to an imager, thereby permitting the lens or lens barrel held by ring member  310  to be aligned with the imager. 
       FIG. 6  illustrates a front view of a lens mount  400  having a plurality of actuator assemblies  440 A/B in accordance with an embodiment of the present invention. Lens mount  400  includes a ring member  410 , a base member  460 , a flexure member  430 , actuator assemblies  440 A/B, and a frame  405 . 
     Ring member  410  is flexibly connected with base member  460  by flexure member  430 . As a result, ring member  410  can remain connected with base member  460  as ring member  410  is translated in various directions, as described herein. Actuator assemblies  440 A/B connect sides (for example, opposite sides) of ring member  410  with frame  405 , allowing ring member  410  to be suspended and supported above base member  460  by actuator assemblies  440 . A lens or lens barrel, such as lens barrel  170  of  FIGS. 1 and 3  can be inserted into an interior space  420  of ring member  410 . The lens or lens barrel can be secured with ring member  410  using threads and/or other appropriate engagement members. 
     Each of actuator assemblies  440 A/B can include an actuator  455 A/B and a flexure member  450 A/B. Actuators  455 A/B can be connected with frame  405  and implemented to move flexure members  450 A/B in a plurality of directions, such as in the directions of arrows  480 . Actuators  455 A/B may be implemented as micro-electro-mechanical systems (MEMS) devices, manually operable mechanisms, or any other appropriate components suitable for moving flexure members  450 A/B. Flexure members  450 A/B can connect actuators  455 A/B with sides of ring member  410 . As a result, actuators  455 A/B can cause ring member  410  to move in response to the motion of flexure members  450 A/B. 
     Force can be applied to flexure members  450 A/B by one or more of actuators  455 A/B. For example, force can be applied by right actuator  455 B to move right flexure member  450 B in a downward direction. As a result, right flexure member  450 B can be moved down to position  470 . In response, ring member  410  can be permitted to move in an arc in the direction of arrow  495  to a translated position  490 . As also illustrated in  FIG. 6 , left flexure member  450 A can be permitted to bend with the movement of ring member  410 , resulting in left flexure member  450 A bending to position  460 . In various embodiments, the operations of left and right actuators  455 A/B as well as left and right flexure members  450 A/B may be interchanged. 
     It will be appreciated that by applying various amounts of force to one or more of flexure members  450 A/B by one or more of actuators  455 A/B, ring member  410  can be translated in a plurality of directions. For example, by selectively applying force from left actuator  455 A or right actuator  455 B, ring member  410  can be made to rotate along at least one axis of rotational freedom in the directions of arrows  465 . It will be appreciated when ring member  410  is moved in the directions of arrows  465 , it can be moved along at least two axes of translational freedom (i.e., along both the X and Y axes denoted in  FIG. 6 ). Moreover, by applying approximately equal force by actuators  455 A/B, ring member  410  can be moved up and down in directions corresponding to one axis of translational freedom (i.e., along the Y axis denoted in  FIG. 6 ). 
     It will be appreciated that actuators  455 A/B can also be implemented to apply force to flexure members  450 A/B in opposite directions. For example, actuator  455 A could be operated to move flexure member  450 A in a downward direction while actuator  455 B is operated to move flexure member  450 B in an upward direction, or vice versa. Such differential operation of actuators  455 A/B can permit ring member  410  to be moved in left and right directions along the X axis denoted in  FIG. 6 . 
     In one embodiment, the lens or lens barrel secured with ring member  410  can be implemented with a focal length of approximately 6.65 mm, and actuators  455 A/B can be operated to move flexure members  450 A/B by approximately 0.050 mm, yielding a range of motion for ring member  410  of approximately ±0.43 degrees in the directions of arrows  465 . In another embodiment, actuators  455 A/B can each be implemented to exert a force of approximately 9.85 mN in the directions of arrows  480 . 
     By moving ring member  410  in relation to the various degrees of freedom as discussed above, the lens or lens barrel secured by ring member  410  can be adjusted in relation to an imager, thereby permitting the lens barrel to be aligned with the imager. 
     It will be appreciated that lens mount  100 ,  200 ,  300 , or  400  may be implemented as part of a camera in various types of personal electronic devices, such as a digital camera, portable computer, a laptop computer, a notebook computer, a pocket personal computer (pocket PC), a personal digital assistant (PDA), a mobile telephone, or any other appropriate personal electronic device.  FIG. 7  illustrates a top view of one such personal electronic device  500 . As illustrated in the embodiment set forth in  FIG. 7 , personal electronic device  500  may include a lens or lens barrel  170  held by lens mount  100 ,  200 ,  300 , or  400 . 
     In view of the present disclosure, it will be appreciated that various features set forth herein provide significant improvements to the alignment of lenses and lens mounts. In particular, the positions of lens mounts  100 ,  200 ,  300 , and  400  can be adjusted with respect to various degrees of freedom in order to appropriately align various lenses or lens barrels secured thereby. 
     The foregoing disclosure is not intended to limit the present invention to the precise forms or particular fields of use disclosed. It is contemplated that various alternate embodiments and/or modifications to the present invention, whether explicitly described or implied herein, are possible in light of the disclosure. 
     For example, ring members  110 ,  310 , or  410  may be implemented as complete rings as illustrated in the accompanying figures, or may alternatively be implemented as portions of rings. As another example, one or more individual or composite lenses may be utilized in place of lens barrel  170  in lens mounts  100 ,  200 ,  300 , and  400  in accordance with alternate embodiments of the present invention. 
     Moreover, the various adjustments described herein can be made in real time to provide image stabilization. For example, tension members  340 A/B and/or actuators  455 A/B can be interfaced with appropriate control circuitry to cause ring members  310  or  410  to move in response to bumps or impacts received by a digital camera. As a result, lenses or lens barrels secured in ring members  310  or  410  can be repeatedly re-aligned with an imager to compensate for such occurrences. 
     Where applicable, the various components set forth herein can be combined with each other and/or separated into sub-components without departing from the spirit of the present disclosure. In addition, where applicable, the ordering of various steps described herein can be changed, combined into composite steps, and/or separated into sub-steps to provide features described herein.