Abstract:
A digital camera module ( 100 ) includes a first sleeve ( 10 ), a first motor ( 20 ), a first barrel ( 30 ), a second sleeve ( 40 ), a second motor ( 50 ) and a second barrel ( 60 ). The first sleeve has at least one lens element ( 142 ) received therein. The first motor is received in the first sleeve. The first barrel has at least one lens element ( 32 ) received therein. The first motor engages with the first barrel and drives the first barrel to axially slide relative to the first sleeve. The second sleeve is located proximate to the first sleeve. The second motor is received in the second sleeve. The second barrel has at least one lens element ( 62 ). The second motor engages with the second barrel and drives the second barrel to axially slide relative to the second sleeve.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to a camera module with a zoom function and a focusing function, and more particularly, to a small-sized digital camera module with a zoom function and a focusing function.  
       DESCRIPTION OF RELATED ART  
       [0002]     With the development of wireless communication technologies, increasing numbers of mobile phones and PDAs now include digital cameras as a special feature.  
         [0003]     Generally speaking, digital cameras are image recording media capable of photographing images without using film. Such a digital camera typically uses an image pickup device, which is a kind of semiconductor device, such as a charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS). In the digital camera, an object image formed on the image pickup device through a lens is converted into an electronic signal by the image pickup device, and the electrical signal is stored as a digital signal, for example, either in the camera unit or in a mobile phone or PDA in which the digital camera is mounted.  
         [0004]     Since the digital camera is to be mounted in a small mobile phone or PDA, a fixed focus lens module is usually used to facilitate mounting thereof. However, images photographed by a digital camera module with a fixed focus lens module tend to be of poor quality. This is partly due to the fixed focus lens, which is incapable of adjusting distance between the lens and the image pickup device to make a clearer image when photographing objects at different distances from the camera. This is also due to the fixed lens, which is incapable of adjusting distance between the lens elements to change the focus of the digital camera module.  
         [0005]     Whichever focusing structure or zoom structure needs a driving apparatus. A typical driving apparatus uses a gear or cam mechanism to realize the focusing or zoom function. This structure is relatively large and makes the camera structure very complicated. Furthermore, the mechanical structure consumes a substantial amount of energy. In addition, the precision of the mechanical transmission is not high.  
         [0006]     Therefore, a digital camera with a zoom function and a focusing function is desired in order to overcome the above-described shortcomings.  
       SUMMARY OF THE INVENTION  
       [0007]     In one embodiment thereof, a digital camera module includes a first sleeve, a first motor, a first barrel, a second sleeve, a second motor and a second barrel. The first sleeve has at least one lens element received therein. The first motor is received in the first sleeve. The first barrel has at least one lens element received therein. The first motor is configured for engaging with the first barrel and drives the first barrel to axially slide relative to the first sleeve. The second sleeve is located proximate to the first sleeve. The second motor is received in the second sleeve. The second barrel has at least one lens element. The second motor engages with the second barrel and drives the second barrel to axially slide relative to the second sleeve.  
         [0008]     Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Many aspects of the digital camera module with the zoom function and focusing function can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the digital camera module with the zoom function and the focusing function. Moreover, in the drawing, like reference numerals designate corresponding parts throughout.  
         [0010]      FIG. 1  is a cut-away view of an embodiment of a digital camera module with a zoom function and a focusing function. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     Referring now to the drawing,  FIG. 1  shows a digital camera module  100  with a zoom function and a focusing function, according to a preferred embodiment. The digital camera module  100  is adapted for use in a portable electronic device such as a mobile phone or a personal digital assistant (PDA), but the compact nature thereof could prove useful in compact digital camera units, digital camcorders or regular film cameras as well. The digital camera module  100  includes a first sleeve  10 , a first motor  20 , a first barrel  30 , a second sleeve  40 , a second motor  50 , a second barrel  60 , an image sensor  70  and a base seat  80 .  
         [0012]     The first sleeve  10  includes a flange  12  and a sleeve body  14  formed together. The flange  12  is formed at a top end of the sleeve body  14 . The flange  12  has a through hole  122  defined in a middle thereof. Several lens elements  124  are set in the through hole  122  of the flange  12 , and receive light that enters from the outside. The sleeve body  14  is a hollow cylinder, and includes a receiving hole  142  cooperatively defined by an inner periphery wall and a bottom wall. The through hole  122  communicates with the receiving hole  142  of the sleeve body  14  so that light can be transmitted therethrough. An axis of the through hole  122  is aligned with that of the receiving hole  142 , and a diameter of the through hole  122  is smaller than that of the receiving hole  142 . Two spaced arms  144  perpendicularly extend from the bottom wall of the sleeve body  14 . Each arm  144  is substantially a long rectangular prism, and a free end of the arm  144  is coplanar with one end of the sleeve body  14  opposite to the flange  12 .  
         [0013]     The first motor  20  is received in the receiving hole  142  of the sleeve body  14 . The first motor  20  includes a plurality of winding coils  22 , a magnet  24  and a rotor  26 . The winding coils  22  form a hollow cylinder, and are mounted on the inner periphery wall of the sleeve body  14 . The winding coils  22  are electrically connected to a power supply of the digital camera module  100 . The magnet  24  is tubular in shape. The magnet  24  is received in the winding coils  22 , and may rotate relative to the winding coils  22 . The rotor  26  is a substantially hollow cylinder, and an inner periphery wall of the rotor  26  defines an inner thread  262 . An outer periphery wall of the rotor  26  is fixed on the inner periphery of the magnet  24 . If the winding coils  22  are energized by current, the winding coils  22  produce a magnetic field. The magnetic field drives the magnet  24  with the rotor  26  to rotate together.  
         [0014]     The first barrel  30  is substantially a hollow cylinder with two open ends so that light can be transmitted therethrough. The first barrel  30  is positioned in the rotor  26 . Zoom lens elements  32  are set in the first barrel  30 . An optical axis of the zoom lens elements  32  is aligned with an optical axis of the lens elements  124 . The first barrel  30  defines an outer thread  34  at an outer periphery wall thereof. The outer thread  34  may engage with the inner thread  262 . The first barrel  30  defines two through cutouts  36  for slidably receiving two arms  144  of the first sleeve  10 .  
         [0015]     The second sleeve  40  is a hollow cylinder, and an outer diameter of the second sleeve  40  is the same as that of the sleeve body  14  of the first sleeve  10 . One end of the second sleeve  40  defines an opening  42 , the other end of the second sleeve  40  defines a containing hole  44 . Two arms  46  extend from a bottom of the second sleeve  40 . Each free end of the arms  46  is coplanar with one end of the second sleeve  40 .  
         [0016]     The second motor  50  is received in the containing hole  44 , and also includes a plurality of winding coils  52 , a magnet  54  and a rotor  56 . The structures of the winding coils  52 , the magnet  54  and the rotor  56  are substantially similar to those of the first motor  20  mentioned above. The difference is that the second motor  50  has a smaller volume than the first motor  20 . Accordingly, the second motor  50  may be driven by less power.  
         [0017]     The second barrel  60  is substantially a hollow cylinder with two open ends so that light can be transmitted therethrough. The second barrel  60  is positioned in the rotor  56 . Focusing lens elements  62  are set in the second barrel  60 . An optical axis of the focusing lens elements  62  is aligned with an optical axis of the zoom lens elements  32 . The second barrel  60  defines an outer thread  64  at an outer periphery wall thereof. The outer thread  64  engages with the inner thread  562 . The second barrel  60  defines two through cutouts  66  for slidably receiving two arms  46  of the second sleeve  40 .  
         [0018]     The image sensor  70  can be a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS). The image sensor  70  may convert the optical image data of an object into electronic signals.  
         [0019]     The base seat  80  is a long cube, and defines a cavity  82  for receiving the image sensor  70 . The base seat  80  may be mounted under the second sleeve  40  for supporting the second sleeve  40 .  
         [0020]     In assembly, the first motor  20  is placed in the first sleeve  10 , and the winding coils  22  are mounted on the receiving hole  142  of the first sleeve  10 . The magnet  24  and the rotor  26  are fixed each other, and are received in the winding coils  22 . Then, the arms  144  are inserted into the cutout  36  of the first barrel  30 , with the outer thread  34  of the first barrel  30  engaging with the inner thread  262  of the rotor  26 . The second motor  50  is placed in the second sleeve  40 , and the winding coils  52  are mounted on the containing hole  44  of the second sleeve  40 . The magnet  54  and the rotor  56  are fixed to each other, and are received in the winding coils  52 . The arms  46  of the second sleeve  40  are inserted into the cutout  66  of the second barrel  60 , with the outer thread  64  of the second barrel  60  engaging with the inner thread  562  of the rotor  56 . After that, one end of the first sleeve  10  opposite to the flange  12  is fixed on the second sleeve  40  by means of adhesion and/or welding. The image sensor  70  is mounted in the base seat  80  by means of adhesive. The image sensor  70  aligns with the axis of the first barrel  30  and the second barrel  60 . Finally, the second sleeve  40  with the first sleeve  10  is fixed on the base seat  80 . The assembly process of the digital camera module  100  is thus completed.  
         [0021]     When taking pictures, the light reflected from an image object (not shown) pass through the lens elements  124 , the zoom lens elements  32  and the focusing lens elements  62 . The lens elements  124 ,  32  and  62  focus the light, after which the light arrives at the image sensor  70 . The image sensor chip  70  transforms the light signal into an electronic signal, permitting the storage of the image information in a memory of the digital camera  100 . As such, the photographic process is finished. If the image is too far away, the user may activate the zoom function. The winding coils  22  are energized by current and the winding coils  22  produce a magnetic field. The magnetic field drives the magnet  24  with the rotor  26  to rotate together. The rotor  26  further brings the first barrel  30  to rotate. However, the first barrel  30  cannot rotate, because the first barrel  30  is limited in movement by the arms  144  of the first sleeve  10 . Thus, the first barrel  30  only slides along the arms  144  relative to the first sleeve  10 . Accordingly, the distance between the zoom lens elements  32  of the first barrel  30  and the lens element  124  is changed, thereby resulting in the stable telescopic movement of the first barrel  30 . The focus distance is thus changed so that a distant object can be imaged in the image sensor  70 .  
         [0022]     After zooming, if the image should prove not to be clear enough (i.e. out of focus), the user may activate the focusing function. The driving principle is similar to the zoom operation. The winding coils  52  are energized by current, and the winding coils  52  produce a magnetic field. The magnetic field drives the magnet  54  with the rotor  56  to rotate together. The rotor  56  further brings the second barrel  60  to rotate. However, the second barrel  60  cannot rotate, because the second barrel  60  is limited in movement by the arms  46  of the second sleeve  40 . Thus, the second barrel  60  only slides along the arms  46  relative to the second sleeve  40 . Accordingly, the distance between the focusing lens elements  62  and the image sensor  70  is changed, thereby resulting in the stable telescopic movement of the second barrel  60 . The image distance is changed so that a distant object can be imaged in the image sensor  70 . When the image becomes clear, the second barrel  60  stops sliding. The second barrel  60  is kept in the focusing position because of the limitation influence of the thread. Thus, the focusing purpose is achieved by changing the distance between the image sensor  70  and the second barrel  60 .  
         [0023]     In alternative embodiments, the first sleeve  10  and the second sleeve  40  may be formed together, and a middle portion is formed on the inner periphery of the sleeve and separates the sleeve portion to be a first sleeve portion and a second sleeve portion. Understandably, the arms of the first sleeve and the second sleeve are connected each other.  
         [0024]     As described above, the preferred embodiment provides a digital camera module  100  with a zoom function and a focusing function for devices such as mobile phones, which has both simplicity and ease of use. It is, however, to be understood that the digital camera module  100  could potentially be useful in other applications in which it may be desirable to allow incoming light to be adjusted so as to attain a clear image.  
         [0025]     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.