Abstract:
An improved lens mount and related alignment methods are provided. In one example, a lens mount includes a ring member and a base member connected with the ring member. The base member has a bottom surface. First and second coplanar mounting pads are provided on the bottom surface of the base member. In another example, a method of aligning a lens mount relative to a stage includes providing a lens mount comprising: a ring member and a base member connected with the ring member. A stage having a top surface is provided. A plurality of alignment members on a bottom surface of the base member are aligned with a corresponding plurality of apertures in the stage. The alignment members are inserted into the apertures, and first, second, and third mounting pads on the bottom surface of the base member are contacted with the top surface of the stage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. patent application Ser. No. 11/041,122 filed on Jan. 21, 2005 now U.S. Pat. No. 7,266,272 entitled “Motion Control Stages and Method of Making the Same”, which is a continuation-in-part of U.S. patent application Ser. No. 10/067,466 entitled “Base, Payload and Connecting Stricture and Methods of Making the Same” filed on Feb. 4, 2002, now U.S. Pat. No. 6,850,675, issued on Feb. 1, 2005, all of which are incorporated herein by reference. 
     In addition, this application claims the benefit of U.S. Provisional Patent Application No. 60/657,261 filed on Feb. 28, 2005 entitled “Autofocus Camera”, which is incorporated herein by reference. 
     In addition, this application 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 is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention generally relates to optics and, more particularly, to lens mounts that are suitable for use with miniature cameras. 
     2. Related Art 
     Optical devices often use one or more lenses to obtain images. In order to provide satisfactory images, it is important that the lenses to be properly aligned with other optical components. For example, in digital cameras, one or more lenses may be used to focus images on an imager. Such lenses may be held in fixed positions or may be mounted in a manner that permits controlled movement of the lenses relative to the imager. However, if the lenses are not properly aligned with respect to the imager, then images captured by the imager may be distorted. 
     The accuracy of lens alignment becomes increasingly important as camera components become miniaturized. In particular, if lenses are misaligned along one or more rotational degrees of freedom, the corresponding pitch, yaw, or roll of the lenses relative to the imager may lead to unsatisfactory image quality. 
     Miniature fixed focus cameras may include lens mounts that are physically interfaced with a printed circuit board onto which an imager is also mounted. The printed circuit board may provide a mounting plane that is perpendicular to an optical axis of one or more lenses secured by the lens mount. As a result, the printed circuit board can form a reference to fix pitch and yaw of the lens mount. 
     Unfortunately, this prior approach to lens mount alignment is not well suited for more sophisticated miniature cameras. In particular, for cameras in which the lenses are moved in relation to the imager to provide focusing and/or zooming features, the lens mount may not always remain fixed in relation to a printed circuit board. 
     Accordingly, there is a need for an improved approach to lens mount design that overcomes the deficiencies in the prior art as discussed above. In particular, there is a need to provide an improved lens mount design 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 includes: a ring member; a base member connected with the ring member, wherein the base member has a bottom surface; and first and second mounting pads on the bottom surface of the base member, wherein the first and second mounting pads are coplanar. 
     In accordance with another embodiment of the present invention, an apparatus adapted to position a lens includes: a lens mount comprising: a ring member, a base member connected with the ring member, wherein the base member has a bottom surface, first, second, and third mounting pads on the bottom surface of the base member, wherein the mounting pads are coplanar, and first and second alignment members on the first and second mounting pads; and a stage comprising: a top surface adapted to receive the first, second, and third mounting pads, and first and second apertures adapted to receive the alignment members. 
     In accordance with another embodiment of the present invention, a personal electronic device includes: a lens mount comprising: a ring member adapted to receive a lens barrel, a base member connected with the ring member, wherein the base member has a bottom surface, first, second, and third mounting pads on the bottom surface of the base member, wherein the mounting pads are coplanar, first and second alignment members on the first and second mounting pads, and first and second alignment surfaces on the first and second alignment members, respectively, wherein the first and second alignment surfaces are substantially perpendicular to the axis of the ring member; a stage comprising: a top surface adapted to receive the first, second, and third mounting pads, first and second apertures adapted to receive the alignment members, and first and second interior surfaces of the stage defining the first and second apertures, respectively, wherein the first and second interior surfaces are substantially parallel to the first and second alignment surfaces of the lens mount, respectively; and an actuator engaged with the stage and adapted to translate the stage in a plurality of directions. 
     In accordance with another embodiment of the present invention, a method of aligning a lens mount relative to a stage includes: providing a lens mount comprising: a ring member, and a base member connected with the ring member, wherein the base member has a bottom surface; providing a stage having a top surface; aligning a plurality of alignment members on a bottom surface of the base member with a corresponding plurality of apertures in the stage; inserting the alignment members into the apertures; and contacting first, second, and third mounting pads on the bottom surface of the base member with the top surface of the stage. 
     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 perspective view of a lens mount in accordance with an embodiment of the present invention. 
         FIG. 2  illustrates a bottom view of a lens mount in accordance with an embodiment of the present invention. 
         FIG. 3  illustrates a front view of a lens mount in accordance with an embodiment of the present invention. 
         FIG. 4  illustrates a side view of a lens mount in accordance with an embodiment of the present invention. 
         FIG. 5  illustrates a perspective view of a lens mount and a stage in accordance with an embodiment of the present invention. 
         FIG. 6  illustrates another perspective view of a lens mount and a stage in accordance with an embodiment of the present invention. 
         FIG. 7  illustrates a perspective view of a lens mount engaged with a stage in accordance with an embodiment of the present invention. 
         FIG. 8  illustrates a personal electronic device incorporating a lens mount, stage, imager, and actuator 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 perspective and bottom views, respectively, of a lens mount  100  in accordance with an embodiment of the present invention. As further described herein, lens mount  100  can be used to mount one or more lenses relative to a stage. Individual lenses may be provided, or the lenses may reside in a lens barrel that is received by lens mount  100 . Advantageously, lens mount  100  can be configured to be mounted on a stage such that three degrees of rotational freedom are resolved to high accuracy, namely pitch, yaw, and roll. Also advantageously, at least two translations can be resolved to high accuracy, namely along an optical axis of the one or more lenses mounted using lens mount  100  (i.e. the axis of a ring member  110  further described herein), and perpendicular to the plane provided by a stage (i.e. stage  200  further described herein). 
     As illustrated, lens mount  100  includes a ring member  110  connected with a base member  120 . In various embodiments, ring member  110  and base member  120  can be a single unitary body or formed from separate components. 
     Ring member  110  defines a cylindrical interior portion  115  which is adapted to receive a lens, lens barrel, and/or other optical components to be mounted using lens mount  100 . Threads (not shown) can also be provided on an interior surface of ring member  110  for securing a threaded lens barrel within cylindrical interior portion  115 . 
     Base member  120  can be substantially rectangular in shape and is adapted to be mounted on a stage  200 , as further described herein. In this regard, base member  120  includes a plurality of coplanar mounting pads adapted to contact stage  200 . In particular, left and right mounting pads  125 , front mounting pad  135 , and rear mounting pad  140  are provided on a bottom surface  160  of base member  120 . 
     As illustrated, left and right mounting pads  125  can be square in shape and situated in proximity to left and right sides, respectively, of bottom surface  160 . Front mounting pad  135  may be implemented as a substantially elongate member situated at a front portion of bottom surface  160  in proximity to a front side of bottom surface  160 . Rear mounting pad  140  may also be implemented as a substantially elongate member situated at a rear portion of bottom surface  160  in proximity to a rear side of bottom surface  160 . It will be appreciated, however, that any of mounting pads  125 ,  135 , and  140  may be implemented using other shapes and/or in other portions of bottom surface  160  as may be desired in particular applications. In various embodiments, greater or fewer numbers of mounting pads may be used. 
     Base member  120  further includes left and right alignment members  130  situated on left and right mounting pads  125 . Alignment members  130  may be sized to be inserted into corresponding apertures in stage  200 , as further described herein. In addition, substantially parallel alignment surfaces  150  are provided on front surfaces of alignment members  130  for further facilitating alignment of lens mount  100  relative to stage  200 , as further described herein. In one embodiment, lens mount  100  and base member  120  are formed using a injection molding process. 
       FIGS. 3 and 4  illustrate front and side views, respectively, of lens mount  100  in accordance with an embodiment of the present invention. It will be appreciated that various components of lens mount  100  previously described herein with regard to  FIGS. 1 and 2  are also visible in the illustrations of  FIGS. 3 and 4 . In particular, left and right mounting pads  125 , front mounting pad  135 , and rear mounting pad  140  can be seen as being coplanar in  FIGS. 3 and 4 . 
       FIGS. 5 and 6  illustrate perspective views of lens mount  100  and stage  200  in accordance with an embodiment of the present invention. Stage  200  may be implemented as a fixed or movable stage. In embodiments where stage  200  is a movable stage, it may be engaged with an actuator  350  (see  FIG. 7 ) configured to translate stage  200  in a plurality of directions, such as toward and away from an imager  300  (see  FIG. 7 ) of a digital camera (for example, in the direction of arrow  250  of  FIG. 7  and/or opposite to the direction of arrow  250 ). Actuator  350  may be implemented in accordance with any appropriate mechanism for providing controlled movements on a scale appropriate for stage  200 . For example, in various embodiments, actuator  350  can be implemented as a Lorentz motor, a micro-electro-mechanical systems (MEMS) device, or other appropriate apparatus. 
     Lens mount  100  and/or stage  200  can be made from any appropriate material such as plastic, silicon, and/or other materials as may be appropriate for particular applications. In one embodiment, the tolerances of components of lens mount  100  and stage  200  can be in the range of approximately zero to approximately 25 microns. 
     Stage  200  includes a top surface  230  adapted to receive mounting pads  125 ,  135 , and  140  of base member  120 . Stage  200  further includes a plurality of apertures  210  adapted to receive alignment members  130  of base member  120 . Front interior surfaces  240  of each of apertures  210  can be implemented as alignment surfaces that are substantially parallel to each other. Front interior surfaces  240  can correspond to alignment surfaces  150  of alignment members  130  in order to aid in the alignment of lens mount  100  with stage  200 , as further described herein. 
     Lens mount  100  may be aligned relative to stage  200  in accordance with several operations as further described herein and illustrated in  FIGS. 5-7 . Alignment members  130  of lens mount  100  can initially be aligned with corresponding apertures  210  of stage  200 . 
     As illustrated in  FIGS. 5 and 6 , lens mount  110  can then be lowered onto stage  200  in the direction of arrows  220 . To aid in the alignment of lens mount  110 , alignment members  130  can be inserted into apertures  210 . It will also be appreciated, however, that stage  200  may alternatively be raised toward lens mount  100  in the direction opposite to arrows  220  while lens mount  110  remains stationary. 
     As lens mount  110  and stage  200  are brought into proximity with each other, alignment members  130  are inserted into apertures  210 . Thereafter, mounting pads  125 ,  135 , and  140  and top surface  230  are brought into contact with each other. In order to permanently or semi-permanently affix lens mount  100  to stage  200 , an adhesive may be introduced to bottom surface  160  of base member  120  and/or to top surface  230  of stage  200  at any desired time prior to the contacting of mounting pads  125 ,  135 , and  140  with top surface  230 . 
       FIG. 7  illustrates a perspective view of lens mount  100  engaged with stage  200  in accordance with an embodiment of the present invention. It will be appreciated that lens mount  100  and stage  200  can be engaged in the manner illustrated in  FIG. 7  after lens mount  100  and stage  200  have been brought into contact with each other, such as by lowering lens mount  100  onto stage  200  in the direction of arrows  220  as illustrated in  FIGS. 5 and 6 . In  FIG. 7 , mounting pads  125 ,  135 , and  140  of base member  120  are illustrated as having been brought in contact with top surface  230  of stage  200 . In addition, alignment members  130  are illustrated as having been inserted into apertures  210  of stage  200 . 
     As previously discussed, mounting pads  125 ,  135 , and  140  can be coplanar. Accordingly, it will be appreciated that when mounting pads  125 ,  135 , and  140  are brought into contact with top surface  230  of stage  200 , lens mount  100  will be fixed relative to stage  200  with regard to at least two rotational degrees of freedom. Specifically, the mounting of coplanar mounting pads  125 ,  135 , and  140  can prevent lens mount  100  from rotating about the X axis (pitch) and Y axis (roll) as illustrated in  FIG. 7 . 
     Following the insertion of alignment members  130  into apertures  210  and the contacting of mounting pads  125 ,  135 , and  140  of base member  120  with top surface  230  of stage  200 , lens mount  100  may be further aligned with respect to stage  200  by moving lens mount  100  in the direction of arrow  250 . As previously discussed, alignment surfaces  150  can be provided on the front members of alignment members  130 , and corresponding front interior surfaces  240  can be provided in the interior of apertures  210 . When lens mount  100  is moved in the direction of arrow  250 , alignment surfaces  150  can be brought in contact with front interior surfaces  240 . Lens mount  100  can be moved in the direction of arrow  250  until both alignment surfaces  150  of base member  120  contact the respective front interior surfaces  240  of apertures  210 . Each of alignment surfaces  150  and front interior surfaces  240  can be implemented to be substantially perpendicular to the axis of ring member  110 . Accordingly, following such contact, front interior surfaces  240  will be substantially parallel to alignment surfaces  150 . 
     It will be appreciated that upon the alignment of alignment surfaces  150  of lens mount  100  with corresponding front interior surfaces  240  of apertures  210 , lens mount  100  can be prevented from rotating about the Z axis (yaw) as illustrated in  FIG. 7 . As a result, following the insertion of alignment members  130  into apertures  210 , the contacting of mounting pads  125 ,  135 , and  140  of base member  120  with top surface  230  of stage  200 , and the moving of lens mount  100  in the direction of arrow  250 , lens mount  100  may be fixed relative to stage  200  such that three degrees of rotational freedom, namely pitch, roll, and yaw, can be resolved to high accuracy. Accordingly, the rotational degrees of freedom of lens mount  100  (as well as any lenses or a lens barrel held by lens mount  100 ) can be fixed relative to an imager  300  of a digital camera. As a result, by aligning stage  200  such that front interior surfaces  240  of apertures  210  are substantially parallel with imager  300 , lens mount  100  and any lenses or lens barrel held by lens mount  100  will also be aligned with imager  300 . 
     It will be appreciated that lens mount  100 , stage  200 , imager  300 , and actuator  350  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. 8  illustrates a top view of one such personal electronic device  400 . As illustrated in the embodiment set forth in  FIG. 8 , personal electronic device  400  may include a lens and/or lens barrel  410  held by lens mount  100 . 
     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. 
     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.