Abstract:
A miniaturized lens assembly includes a front lens portion, a rear lens portion, a large diaphragm plate mounted between the front and rear lens portions, a small diaphragm plate rotatable relative to the large diaphragm plate, a shutter plate rotatable relative to the large diaphragm plate, first and second actuating elements mounted on the rear lens portion, and two pivot axles mounted between the front and rear lens portions. The miniaturized lens assembly is miniature in size, is simple in structure, and is easy to assemble.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims priority of Taiwanese Application No. 093129021, filed on Sep. 24, 2004. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a lens assembly, more particularly to a miniaturized lens assembly. 
   2. Description of the Related Art 
   Referring to  FIGS. 1 ,  2  and  3 , a conventional lens assembly includes a shell unit  1 , a lens unit  2  received in the shell unit  1 , and a motor  3  for actuating the lens unit  2 . 
   The shell unit  1  has a peripheral wall  101  and a guiding groove  102  in the peripheral wall  101 . 
   The lens unit  2  has a front lens portion  4 , a rear lens portion  5  opposite to the front lens portion  4  along a longitudinal axis (X), a large diaphragm plate  6  mounted between the front lens portion  4  and the rear lens portion  5 , a small diaphragm plate  7  mounted pivotally between the front lens portion  4  and the rear lens portion  5  and rotatable relative to the large diaphragm plate  6 , a shutter plate  8  mounted pivotally between the front lens portion  4  and the rear lens portion  5  and rotatable relative to the large diaphragm plate  6 , a connecting member  9  mounted pivotally on the shell unit  1  and connected to the shutter plate  8 , and an electromagnetic actuator  901  mounted on the shell unit  1  for actuating the connecting member  9 . 
   The large diaphragm plate  6  has a large aperture  601  along the longitudinal axis (X). The small diaphragm plate  7  has a coupling end portion  701  movably anchored in the guiding groove  102  of the shell unit  1 , and a small aperture  702  for overlapping or moving away from the large aperture  601 . The shutter plate  8  has an actuated portion  801  and a shading portion  802  for covering or moving away from the large aperture  601 . The connecting member  9  is mounted outside the front lens portion  4 , and has a pivoting portion  902 , an actuated end portion  903  extending from the pivoting portion  902  and actuated by the electromagnetic actuator  901 , and a transmitting end portion  904  opposite to the actuated end portion  903  and coupled to the actuated portion  801 . 
   When the motor  3  is actuated to move the lens unit  2  along the longitudinal axis (X), the switching between the large and small apertures  601 , 702  can be achieved through the action of the coupling end portion  701  in the guiding groove  102 . As shown in  FIGS. 2 and 4 , when the actuated end portion  903  of the connecting member  9  is actuated by the electromagnetic actuator  901 , the actuated portion  801  of the shutter plate  8  can be actuated by the transmitting end portion  904  so that the shading portion  802  of the shutter plate  8  can be moved relative to the large aperture  601  to shade or move away from the latter so as to achieve the purpose of controlling the shutter plate  8 . 
   Although the switching between the large and small apertures  601 , 702  and the control of the shutter plate  8  can be achieved in the aforesaid conventional lens assembly, the following disadvantages are encountered: 
   1. Since the shutter plate  8  is controlled by the pivotal movement of the connecting member  9  actuated by the electromagnetic actuator  901 , the volume occupied thereby is relatively large. 
   2. Since the switching between the large and small apertures  601 , 702  is conducted by the cooperation of the small diaphragm plate  7  and the guiding groove  102  of the shell unit  1 , and since the control of the shutter plate  8  is actuated by the pivotal movement of the connecting member  9 , testing of the lens unit  2  is conducted after the lens unit  2  is installed on the shell unit  1 . If the lens unit  2  needs to be modified or adjusted after the test, it is required to disassemble the same from the shell unit  1 . Therefore, the process for making the conventional lens assembly is troublesome. 
   3. The transmitting end portion  904  of the connecting member  9  should have a length sufficient for the operation of the lens unit  2 , and should be inserted between the front and rear lens portions  4 , 5  in order to connect to the actuated portion  801  of the shutter plate  8  interposed between the front and rear lens portions  4 , 5 . Therefore, the installation of the conventional lens assembly is relatively complicated. 
   4. The accuracy of the action of the shutter plate  8  may be affected by the accumulated tolerance of the amount of the magnetic affinity of the electromagnetic actuator  901 , the clearance between the transmitting end portion  904  of the connecting member  9  and the shutter plate  8 , the clearance between the pivoting portion  902  of the connecting member  9  and the shell unit  1 , and the like. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a miniaturized lens assembly which is simple in structure, which is miniature in size, and which is relatively easy to assemble and convenient to test. 
   Therefore, a miniaturized lens assembly according to this invention includes a lens unit, which has a front lens portion, a rear lens portion opposite to the front lens portion, a large diaphragm plate mounted between the front lens portion and the rear lens portion, a small diaphragm plate mounted pivotally between the front lens portion and the rear lens portion and rotatable relative to the large diaphragm plate, a shutter plate mounted pivotally between the front lens portion and the rear lens portion and rotatable relative to the large diaphragm plate, first and second actuating elements mounted on the rear lens portion, and two pivot axles mounted between the front and rear lens portions and distal from each other. The large diaphragm plate has a large aperture. The small diaphragm plate has a first pivot portion pivotally connected to one of the pivotal axles, a swing portion opposite to the first pivot portion, a first actuated portion proximate to the first pivot portion, and a small aperture provided in the swing portion. The first actuated portion is actuated by the first actuating element to move the small diaphragm plate between a first position in which the small aperture is aligned with the large aperture, and a second position in which the small aperture is moved away from the large aperture. The shutter plate has a second pivot portion pivotally connected to the other of the pivot axles, a shading portion opposite to the second pivot portion, and a second actuated portion proximate to the second pivot portion. The second actuated portion is actuated by the second actuating element to move the shutter plate between an open position in which the shading portion is away from the large aperture, and a closed position in which the shading portion covers the large aperture. The first and second actuating elements respectively have actuating portions connected to the first and second actuated portions, respectively. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which: 
       FIG. 1  is a perspective view of a conventional lens assembly; 
       FIG. 2  is a top view of the conventional lens assembly; 
       FIG. 3  is a sectional view taken along line  3 — 3  of  FIG. 2 ; 
       FIG. 4  is another top view of the conventional lens assembly showing the movement of a shutter plate of the conventional lens assembly; 
       FIG. 5  is an exploded perspective view of the preferred embodiment of a miniaturized lens assembly according to this invention; 
       FIG. 6  is a sectional view of the preferred embodiment; 
       FIG. 7  is a schematic view showing a state in which a small diaphragm plate and a large diaphragm plate of the preferred embodiment are aligned with each other; 
       FIG. 8  is a schematic view showing a state in which the small diaphragm plate and the large diaphragm plate of the preferred embodiment are moved away from each other; 
       FIG. 9  is a schematic view showing a state in which a shutter plate of the preferred embodiment is moved away from the large diaphragm plate; and 
       FIG. 10  is a schematic view showing a state in which the shutter plate covers the large diaphragm plate. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 5 and 6 , the preferred embodiment of the miniaturized lens assembly according to this invention includes a shell unit  100 , a lens unit  200  mounted in the shell unit  100 , and a motor  300  mounted on the shell unit  100  for actuating the lens unit  200 . As the configuration for connecting the motor  300  to the lens unit  200  is well known to the skilled artisan, it will not be described herein in detail. 
   The shell unit  100  includes a receiving box  11  having a lens hole  111 , and a cap  12  having a lens hole  121  aligned with the lens hole  111  of the receiving box  11  along a longitudinal axis (L). The receiving box  11  cooperates with the cap  12  to define a receiving space  13  for receiving the lens unit  200 . The lens hole  121  of the cap  12  is formed as a stepped hole configuration, and includes a large diameter ring portion  122 , a small diameter ring portion  123 , a shoulder face  124  between the large and small diameter ring portions  122 ,  123 , and an annular groove  125  formed in the shoulder face  124 . The shell unit  100  further includes a protecting lens  14  mounted to the large diameter ring portion  122 , and a leak-proof element  15  mounted in the annular groove  125  to achieve air-tight and water-proof effects for the lens hole  121  of the cap  12 . 
   The lens unit  200  is mounted in the receiving space  13 , and includes a front lens portion  21  proximate to the cap  12 , a rear lens portion  22  opposite to the front lens portion  21  and distal from the cap  12 , a large diaphragm plate  23  mounted between the front lens portion  21  and the rear lens portion  22 , a small diaphragm plate  24  mounted pivotally between the front lens portion  21  and the rear lens portion  22  and rotatable relative to the large diaphragm plate  23 , a shutter plate  25  mounted pivotally between the front lens portion  21  and the rear lens portion  22  and rotatable relative to the large diaphragm plate  23 , first and second actuating elements  26 , 27  mounted on the rear lens portion  22 , and first and second pivot axles  221 , 222  mounted between the front and rear lens portions  21 , 22  and distal from each other. In the preferred embodiment, the first and second pivot axles  221 , 222  are mounted on the rear lens portion  22  and protrude toward the front lens portion  21 . 
   Referring to  FIG. 7 , the large diaphragm plate  23  has a large aperture  231 . The small diaphragm plate  24  has a first pivot portion  241  pivotally connected to the first pivotal axle  221 , a swing portion  242  opposite to the first pivot portion  241 , a first actuated portion  243  proximate to the first pivot portion  241 , and a small aperture  244  provided in the swing portion  242 . The first actuated portion  243  has an elongate hole  2431 . The first actuating element  26  includes an electromagnetically operated rod  261  slidable in the elongated hole  2431  in the small diaphragm plate  24 . 
   Referring to  FIGS. 5 and 9 , the shutter plate  25  has a second pivot portion  251  pivotally connected to the second pivot axle  222 , a shading portion  252  opposite to the second pivot portion  251 , and a second actuated portion  253  proximate to the second pivot portion  251 . The second actuated portion  253  has an elongate hole  2531 . The second actuating element  27  includes an electromagnetically operated rod  271  slidable in the elongated hole  2531  in the shutter plate  25 . 
   Referring to  FIGS. 7 and 8 , when a camera including the miniaturized lens assembly of this invention is operated by a user, the result of light detection is transmitted to the lens unit  200 . The first actuated portion  243  can be actuated by the first actuating element  26  to move the small diaphragm plate  24  from a first position in which the small aperture  244  is aligned with the large aperture  232 , to a second position in which the small aperture  244  is moved away from the large aperture  231 . 
   Referring to  FIGS. 9 and 10 , when the second actuating element  27  is driven by the user through operation of a button (not shown), the second actuated portion  253  is actuated by the second actuating element  27  to move the shutter plate  25  from an open position in which the shading portion  252  is away from the large aperture  231 , to a closed position in which the shading portion  252  covers the large aperture  231  so as to achieve the purpose of controlling the exposure time. 
   In view of the aforesaid, the miniaturized lens assembly of this invention has the following advantages: 
   1. The small diaphragm plate  24  and the shutter plate  25  are controlled respectively by the first and second actuating elements  26 , 27 , which are mounted on the rear lens portion  22 . The lens unit  200  is constructed by assembling the front lens portion  21 , the rear lens portion  22 , the large diaphragm plate  23 , the small diaphragm plate  24 , the shutter plate  25 , the first actuating element  26 , and the second actuating element  27  together. Therefore, the lens assembly of this invention is miniaturized as compared to the conventional lens assembly. 
   2. The first and second actuating elements  26 , 27  for respectively actuating the small diaphragm plate  24  and the shutter plate  25  are mounted on the rear lens portion  22 , rather than on the shell unit  100 . Therefore, testing of the lens unit  200  can be conducted before being mounted in the shell unit  100 . The process for making the miniaturized lens assembly of this invention is simplified accordingly. 
   3. The first and second pivot axles  221 , 222  are mounted on the rear lens portion  22 . The electromagnetically operated rod  261  of the first actuating element  26  and the electromagnetically operated rod  271  of the second actuating element  27  can be recognized easily after the first and second actuating elements  26 , 27  are mounted on the rear lens portion  22 . Therefore, the large diaphragm plate  23 , the small diaphragm plate  24 , and the shutter plate  25  can be assembled with relative ease. 
   4. The small diaphragm plate  24  and the shutter plate  25  are actuated directly by the first actuating element  26  and the second actuating element  27 , respectively. No additional coupling mechanism is required between the small diaphragm plate  24  and the first actuating element  26  or between the shutter plate  25  and the second actuating element  27 . Therefore, the accuracy for controlling movement of the small diaphragm plate  24  and the shutter plate  25  is increased. 
   While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.