Abstract:
A device for arranging a distance between an optical element and an image sensor. The device includes a housing mechanically coupled to the optical element, a frame mechanically coupled to the housing, the frame having a first extension, and a base movably coupled to the frame, the base having a sloped first channel accommodating the first extension, the first channel having a first stop point and a second stop point, wherein the frame moves between the first stop point and the second stop point, which correspond to first and second distances between the optical element and the image sensor, respectively.

Description:
[0001]     This application claims priority to U.S. Provisional Patent Application Ser. No. 60/547,195, filed on Feb. 24, 2004, and also claims priority to U.S. Provisional Patent Application 60/547,194, filed on Feb. 24, 2004. The disclosures of these applications are incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     1. Technical Field  
         [0003]     The present disclosure relates to a method and apparatus for macro-focus feature for a camera. More specifically, the present disclosure relates to a method and apparatus for macro-focus feature for a camera module in a portable device such as a cellular phone, personal digital assistant (PDA) or any device capable of capturing a digital image.  
         [0004]     2. Background of the Invention  
         [0005]     Macro-focus refers to a camera&#39;s ability to focus on a nearby object and may be achieved by repositioning a lens in the camera in order to focus on the nearby object. Such repositioning may be performed by moving a lens-barrel within a lens-mount in order to bring a lens within the lens-barrel to a macro-focus position. It may be desirable to include a macro-focus feature capable of focusing the lens at macro-focus and infinity-focus positions repeatedly and accurately. Providing this function in an accurate and repeatable manner while allowing for size and cost considerations may be challenging, especially in implementations such as cellular phones or PDA&#39;s.  
         [0006]     With a macro-focus feature, the lens-barrel may move between the two or more focus positions. However, variations in the manufacturing process may produce slack, thereby negatively affecting the repeatability and accuracy of the movement of the lens-barrel into the focus positions.  
       SUMMARY  
       [0007]     The present disclosure relates to a method and apparatus for arranging a distance between an optical element and an image sensor, comprises a housing mechanically coupled to the optical element, a frame mechanically coupled to the housing, the frame having a first extension, and a base movably coupled to the frame, the base having a sloped first channel accommodating the first extension, the first channel having a first stop point and a second stop point, wherein the frame moves between the first stop point and the second stop point, which correspond to first and second distances between the optical element and the image sensor, respectively.  
         [0008]     In another aspect, the frame includes a cantilever extension, and the base includes a sloped cantilever channel accommodating the cantilever extension.  
         [0009]     In another aspect, the cantilever channel has substantially the same slope as the first channel, the cantilever channel is at least as long as the first channel, and the cantilever channel and first channel are separated by a predetermined distance, and the first extension and the cantilever extension are separated by the predetermined distance.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The foregoing features and other aspects of the present disclosure are explained in the following description taken in connection with the accompanying drawings, wherein:  
         [0011]      FIG. 1  is a view of a camera module having a macro-focus feature, according to one aspect of the present disclosure.  
         [0012]      FIGS. 2A and 2B  are views of a lens-barrel, according to one aspect of the present disclosure.  
         [0013]      FIGS. 3A, 3B  and  3 C are views of a lens-mount, according to one aspect of the present disclosure.  
         [0014]      FIGS. 4A, 4B ,  4 C and  4 D are views of a macro-ring, according to one aspect of the present disclosure.  
         [0015]      FIG. 5  is a view of a button, according to one aspect of the present disclosure.  
         [0016]      FIG. 6  is a perspective view of a lens-mount, according to another aspect of the present disclosure.  
         [0017]      FIGS. 7A, 7B ,  7 C,  7 D and  7 E are top, bottom, side, and cross-section views of a lens-mount, according to another aspect of the present disclosure.  
         [0018]      FIG. 8A  is a side cross-sectional view of a lens-mount according to another aspect of the present disclosure.  
         [0019]      FIG. 8B  is a top detail view of the lens-mount according to another aspect of the present disclosure.  
         [0020]      FIG. 9A  is a side view of a lens-mount according to another aspect of the present disclosure.  
         [0021]      FIG. 9B  is a view of a slot according to another aspect of the present disclosure.  
         [0022]      FIG. 10  is a perspective view of a macro-ring, according another aspect of the present disclosure.  
         [0023]      FIGS. 11A, 11B  and  11 C are side and top views of a macro-ring, according another aspect of the present disclosure.  
         [0024]      FIGS. 12A, 12B ,  12 C, and  12 D are top and side views of a macro-ring, according another aspect of the present disclosure.  
         [0025]      FIGS. 12E and 12F  are top cross-section views of tab and button according to another aspect of the present disclosure. 
     
    
     DETAILED DESCRIPTION  
       [0026]      FIG. 1  is a view of a camera module having a macro-focus feature, according to one aspect of the present disclosure. Camera module  100  may include lens-barrel  200 , lens-mount  300 , and macro-ring  400 . Lens-barrel  200  may be secured to macro-ring  400 , and macro-ring  400  may be movably attached to lens-mount  300 .  
         [0027]      FIGS. 2A and 2B  are views of a lens-barrel, according to one aspect of the present disclosure. Lens-barrel  200  may include lens-barrel threads  202 . Section  204  of lens-barrel  200  may be partially flat and may provide for axial self-aligning lens-barrel  200  to macro-ring  400 . Opening  206  may permit light to pass to lens (not shown) located within lens-barrel  200 . Raised portion  208  may be a shape, such as an hexagon, and may be used as a contact point used to move lens-barrel  200 , for example, during assembly and calibration.  
         [0028]      FIGS. 3A, 3B  and  3 C are views of a lens-mount according to one aspect of the present disclosure. Lens-mount  300  may include one or more sloped channels  302 . Channel  302  may include focus stops  304  and  306  corresponding to focus positions, for example infinity and macro-focus. Focus stops  304  and  306  may be detents or depressions molded into lens-mount  300  and may provide positive locking stopping points for the movement of macro-ring  400 . Additional detents may be added, providing intermediate focus positions. In another aspect, channel  302  may be substantially vertically oriented.  
         [0029]     As macro-ring  400  moves, channel  302  in lens-mount  300  guides macro-ring  400  and lens-barrel  200  toward or away from the image sensor (not shown), depending on the direction of movement, thereby changing the focus distance. The slope of channel  302  determines the amount of movement necessary to move between focus positions.  
         [0030]     Slot  308  may facilitate insertion of tab  404  and button  406  into the channels  302 . Lens-mount  300  may act as a cover for the image sensor (not shown), and opening  310  may permit light to pass to the image sensor (not shown).  
         [0031]      FIGS. 4A, 4B ,  4 C and  4 D are views of a macro-ring, according to one aspect of the present disclosure. Macro-ring  400  may have internal threads  402  for threading with lens-barrel threads  202 . Macro-ring  400  may have one or more tabs  404 , each with button  406 . Tab  404  may flex inward when inserted into lens-mount  300 , until button  406  reaches channels  302 .  
         [0032]     Each button  406  may be shaped to provide a spring action to allow for positive locking in the focus positions. An example of button  406  is shown in  FIG. 5 . When lens-barrel  200  is inserted into macro-ring  400 , tabs  404  may not retract due to mechanical interference with lens-barrel  200 , thereby preventing macro-ring  400  from exiting lens-mount  300 .  
         [0033]     Holes  408  in macro-ring  400  may be openings for glue and/or heat staking macro-ring  400  to lens-barrel  200 .  
         [0034]     Interface  410  may provide for physical control of macro-ring  400  and the macro-focus feature. In one aspect, interface  410  may be a tab, as shown in  FIGS. 4A, 4B  and  4 C. In another aspect, interface  410  may include teeth (not shown) that interface with a driving gear (not shown).  
         [0035]     A camera module  100  having a macro-focus feature may be assembled as follows:  
         [0036]     Macro-ring  400  may be inserted into lens-mount  300  and positioned in a focus position, for example, the infinity focus position.  
         [0037]     Lens-barrel  200  may be inserted into macro-ring  400  by threading lens-barrel threads  202  with macro-ring threads  402 . Image sensor (not shown) beneath lens-mount  300  may be contacted electrically and activated.  
         [0038]     Lens-barrel  200  may be moved until an image obtained from the image sensor reaches best focus position for the given focus position, in this example, infinity.  
         [0039]     Macro-ring  400  and lens-barrel  200  may be securely attached to each other by dropping glue into one or more holes  408  in macro-ring  400 . After the glue is dispensed, macro-ring  400  may be heat staked to lens-barrel  200  to ensure robustness of the connection between macro-ring  400  and lens-barrel  200 . In another aspect, heat staking may be sufficient for fixing lens-barrel  200  to macro-ring  400  without glue.  
         [0040]     FIGS.  6 ,  7 A- 7 E,  8 A,  8 B,  9 A and  9 B are views of a lens-mount, according to another aspect of the present disclosure. As shown in  FIG. 6 , lens-mount  600  may include one or more sloped channels  602 . Each channel  602  may include focus stops  604  and  606  corresponding to focus positions, for example, macro-focus and infinity. Focus stops  604  and  606  may be detents or depressions molded into lens-mount  600  and may provide positive locking stopping points for the movement of macro-ring  1000 . In one aspect, additional focus stops may be added, providing intermediate focus positions. In another aspect, channel  602  may be substantially vertically oriented. In one aspect, detents are located along a top portion of channel  602 .  
         [0041]     Lens-mount  600  may act as a cover for the image sensor (not shown), while opening  610  may permit light to pass to the image sensor (not shown). Lens-mount  600  may include a raised platform  612  surrounding opening  610  at the bottom of the lens-mount cavity which may prevent flashing or other particulates from reaching the lens or image sensor (not shown).  
         [0042]     Lens-mount  600  may include a sloped cantilever channel ramp  614  that contacts and maintains constant force against cantilever spring  1012  through cantilever spring interface  1014 , located on macro-ring  1000 , as described below. The lengths and arrangements of channel  602  and cantilever channel ramp  614  may be related so that cantilever spring interface  1014  is in contact with cantilever channel ramp  614  as tab  1004  and button  1006  move along channel  602 .  
         [0043]     Following in a circular pattern around platform  612 , at the end of cantilever channel ramp  614  there may be a substantially horizontal trench  616 . Following trench  616  may be another cantilever channel ramp  614  and so on. Each cantilever channel ramp  614  and trench  616  combination may correspond to a channel  602 .  
         [0044]     As shown in  FIG. 8A , cantilever channel ramp  614  and trench  616  may be located at a height lower than platform  612 , and flashing or particulates may collect there. Oil, grease or other substances likely to retain flashing or particulates may be added to cantilever channel ramp  614  and/or trench  616  to prevent flashing or particulates from crossing platform  612  and reaching opening  610  and image sensor (not shown).  
         [0045]     As shown in  FIGS. 8A, 8B  and  9 A lens-mount  600  may include slot  608  with sloped edge surface having increasing thickness in a downward direction, thereby providing increasing force against tab  1004  and button  1006  during insertion of button  1006  of macro-ring  1000  into channel  602  of lens-mount  600 .  
         [0046]     As the macro-ring  1000  moves, for example, rotates, channel  602  in lens-mount  600  guides macro-ring  1000  and lens-barrel  200  toward or away from the image sensor (not shown), depending on the direction of movement, thereby changing the focus distance. The slope of channel  602  determines the movement necessary to move between focus positions.  
         [0047]     FIGS.  10 ,  11 A- 11 C and  12 A- 12 F are views of a macro-ring, according to another aspect of the present disclosure.  
         [0048]     Macro-ring  1000  may have one or more cantilever springs  1012  each with a cantilever spring interface  1014 . Cantilever spring  1012  may ensure that button  1006  moves along a top surface of channel  602  by applying force on cantilever channel ramp  614 . Cantilever spring  1012  assists pushing button  1006  into focus stops  604  and  606 , or any intermediate focus stops as provided. Cantilever spring  1012  may flex upward when macro-ring  1000  is inserted into the lens-mount.  
         [0049]     Macro-ring  1000  may have internal threads  1002  for threading with lens-barrel threads  202 . Macro-ring  1000  may have one or more tabs  1004 , each with button  1006 . Tab  1004  may flex inward when inserted along tapered portion of slot  608  into lens-mount  600 , until button  1006  reaches channel  602 .  
         [0050]     Button  1006  may be shaped to provide a spring action to allow for positive locking in focus stops  604  and  606 . When lens-barrel  200  is inserted into macro-ring  1000 , tab  1004  may not retract due to mechanical interference with lens-barrel  200 , thereby preventing macro-ring  1000  from exiting lens-mount  600 .  
         [0051]     Macro-ring  1000  may also have posts  1016  and  1018  that may make contact with lens-mount  600  when excess downward force is applied to macro-ring  1000 , for example during insertion into lens-mount  600 , thereby preventing damage to cantilever spring  1012  and tab  1004 .  
         [0052]     Interface  1010  may provide for physical control of macro-ring  1000  and the macro-focus feature. In one aspect, interface  1010  may be a tab, as shown in  FIGS. 10, 11A  and  11 B. In another aspect, interface  1010  may include teeth (not shown) that interface with a driving gear (not shown).  
         [0053]     A camera module having a macro-focus feature may be assembled as follows:  
         [0054]     Macro-ring  1000  may be inserted into lens-mount  600  by aligning button  1006  with slot  608  and pressing together macro-ring  1000  and lens-mount  600 . Tab  1004  may flex inward as button  1006  rides downward along slot  608  until button  1006  reaches channel  602 . Once inserted into lens-mount  600 , macro-ring  1000  may be moved, for example, rotated, thereby causing cantilever spring interface  1014  to slide along cantilever channel ramp  614  and causing button  1006  to move along a top surface of channel  602  until button  1006  reaches a focus stop, e.g. focus stop  604 , which causes the macro-ring  1000  to stop moving.  
         [0055]     Lens-barrel  200  may be inserted into macro-ring  1000  by threading lens-barrel threads  202  with macro-ring threads  1002 .  
         [0056]     The image sensor (not shown) beneath the lens-mount  600  may be contacted electrically and activated.  
         [0057]     Lens-barrel  200  may be moved, for example, rotated, until an image obtained from the image sensor reaches best focus position for the given focus position.  
         [0058]     Lens barrel  200  may be attached to macro-ring  1000  by glue, or it may be heat staked or attached by laser staking.  
         [0059]     Although illustrative embodiments have been described herein in detail, it should be noted and will be appreciated by those skilled in the art that numerous variations may be made within the scope of this invention without departing from the principle of this invention and without sacrificing its chief advantages.  
         [0060]     Unless otherwise specifically stated, the terms and expressions have been used herein as terms of description and not terms of limitation. There is no intention to use the terms or expressions to exclude any equivalents of features shown and described or portions thereof and this invention should be defined in accordance with the claims that follow.