Abstract:
A lens cover module includes a rail member, a lens cover movably mounted on the rail member, a first driving device, and a second driving device. The lens cover reciprocates between a first position where the lens cover covers the lens, and a second position, where the lens cover uncovers the lens. The first driving device moves the lens cover from the first position to a third position, and moves the lens cover from the second position to a fourth position. After the first driving device, the second driving device keeps moving the lens cover to the second position from the third position, or moving the lens cover to the first position from the fourth position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to an image device, and more particularly to a lens cover module. 
         [0003]    2. Description of the Related Art 
         [0004]    With advancement in image technology, image devices, such as video camera, camera, and projector, are widely used in ordinary home life. For example, projector is one of the most popular machines used in business, education, and home life. 
         [0005]    The image device usually is provided with a lens to catch images or project image. The quality of image will be poor when the lens is scratched or covered by dust. Typically, the conventional lens cover engages a front end of the lens and will be manually taken off that user always searches for the lens cover if he/she forgot where to put it. 
         [0006]    Taiwan patent 512255 taught a power lens cover, in which the image device has a built-in lens cover to be moved by a motor. The lens cover cannot be taken off from the image device, but it is very complex and is hard to repair. Besides, the motor will make noise when it moves the lens cover, and the lens cover will close only when the power is turned on again, and this will affects user to conveniently use the image device. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary objective of the present invention is to provide a lens cover module, which uses a simple structure to open or close the lens cover. 
         [0008]    According to the objective of the present invention, the present invention provides lens cover module for covering or uncovering a lens, including a rail member, a lens cover movably mounted on the rail member, a first driving device, and a second driving device. The lens cover reciprocates between a first position where the lens cover covers the lens, and a second position where the lens cover uncovers the lens. The first driving device moves the lens cover from the first position to a third position, and moves the lens cover from the second position to a fourth position. Both the third and the fourth position are between the first position and the second position. The second driving device moves the lens cover from the third position to the second position after the first driving device moves the lens cover from the first position to the third position, and moves the lens cover from the fourth position to the first position after the first driving device moves the lens cover from second the position to the fourth position. 
         [0009]    In an embodiment, the first driving member has a least a magnetic driven member on the lens cover and at least a magnetic member so that the magnetic member generates a magnetic field to drive the magnetic driven member to move the lens cover. 
         [0010]    In an embodiment, the magnetic driven member has a first magnetic driven member and a second magnetic driven member so that the magnetic member generates a magnetic field to drive the first magnetic driven member to move the lens cover from the first position to the third position, or the magnetic member generates a magnetic field to drive the second magnetic driven member to move the lens cover from the second position to the fourth position. 
         [0011]    In an embodiment, the magnetic member a first magnetic member and a second magnetic member so that the first magnetic member generates a magnetic field to drive the first magnetic driven member to move the lens cover from the first position to the third position, and the second magnetic member generates a magnetic field to drive the second magnetic driven member to move the lens cover from the second position to the fourth position. 
         [0012]    In an embodiment, the lens cover module further includes a controller electrically connected to the first magnetic member and the second magnetic member to control the first magnetic member or the second magnetic member to generate the magnetic field. 
         [0013]    In an embodiment, the magnetic member has a first magnetic member and a second magnetic member so that the first magnetic member generates a magnetic field to drive the magnetic driven member to move the lens cover from the first position to the third position, and the second magnetic member generates a magnetic field to drive the magnetic driven member to move the lens cover from the second position to the fourth position. 
         [0014]    In an embodiment, the lens cover module further provides a controller electrically connected to the first magnetic member and the second magnetic member to control the first magnetic member or the second magnetic member to generate the magnetic field. 
         [0015]    In an embodiment, the lens cover module further provides at least a detection device to sense whether the lens cover arrives the third position or arrives the fourth position. 
         [0016]    In an embodiment, the detection device includes a first detection device to sense whether the lens cover arrives the third position and a second detection device to sense whether the lens cover arrives the fourth position. 
         [0017]    In an embodiment, the first driving device stops to move the lens cover when the detection device senses the lens cover at the third position, and the second driving device takes over to move the lens cover to the second position. 
         [0018]    In an embodiment, the first driving device stops to move the lens cover when the detection device senses the lens cover at the fourth position, and the second driving device take over to move the lens cover to the first position. 
         [0019]    In an embodiment, the rail member has a rail and a slider movably mounted on the rail, and the lens cover is connected to the slider to move on the rail. 
         [0020]    In an embodiment, the second driving device is a torsional spring having opposite ends pivoted on the slider and the rail. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is an exploded view of a preferred embodiment of the present invention; 
           [0022]      FIG. 2  is a sketch diagram of the preferred embodiment of the present invention, showing the lens cover at the first position; 
           [0023]      FIG. 3  is a sketch diagram of the preferred embodiment of the present invention, showing the lens cover at the second position; 
           [0024]      FIG. 4  shows the rail member and the second driving device of the preferred embodiment of the present invention; 
           [0025]      FIG. 5  is a sketch diagram of the preferred embodiment of the present invention, showing the lens cover moving from the first position toward the second position; and 
           [0026]      FIG. 6  is a sketch diagram of the preferred embodiment of the present invention, showing the lens cover moving from the second position toward the first position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    As shown in FIGS. from  FIG. 1  to  FIG. 3 , a lens cover module  1  for shielding or unshielding a lens  200  includes a case  10 , a rail member  14 , the lens cover  100 , a driving device, a controller  40 , and first and second detection devices  51 ,  52 . 
         [0028]    The case  10  has an opening  12  aligned with the lens  200 . 
         [0029]    The rail member  14  is mounted on the case  10  beside the opening  12 . As shown in  FIG. 4 , the rail member  14  includes a rail  141 , a slider  142  movably mounted on the rail  141 . 
         [0030]    The lens cover  100  engages slider  142  of the rail member  14  to reciprocate along the rail  141  between a first position ( FIG. 2 ) where the lens cover  100  is in front of the lens  200  to cover the lens  200  and a second position ( FIG. 3 ) where the lens cover  100  is removed from the lens  200  to expose the lens  200 . In the first position, the lens cover  100  is between the opening  12  and the lens  200  to shield the opening  12 . 
         [0031]    The driving device includes a first driving member and a second driving member  60 . The first driving member has first and second magnetic driven members  21 ,  22  and first and second magnetic members  31 ,  32 . The first and the second magnetic driven members  21 ,  22  are mounted on the lens cover  100 . In the present invention, the first and the second magnetic driven members  21 ,  22  are iron plates. In practice, the magnetic driven members  21 ,  22  may be anything that can be driven by magnetic force, such as magnets. 
         [0032]    The first and the second magnetic members  31 ,  32  are mounted on the case  10 . The first magnetic member  31  generates a magnetic field to drive the first magnetic driven member  21  to move the lens cover  100  to a third position from the first position. The third position is between the first position and the second position, and is closer to the second position. The second magnetic member  32  generates a magnetic field to drive the second magnetic driven member  22  to move the lens cover  100  to a fourth position from the second position. The fourth position is between the first position and the second position, and is closer to the first position. In the present invention, the first and the second magnetic members  31 ,  32  are electromagnets, and they are not limited in electromagnets. The magnetic members in the present embodiment may use any device or element which generates magnetic force or power. 
         [0033]    The second driving member  60  is connected to the rail member  14  to take over the first driving member to move the lens cover  100  to the first position from the fourth position or to the second position from the third position. In the present invention, the second driving member  60  is a torsional spring, as shown in  FIG. 4 . The second driving member  60  has two arms  61 , and distal ends of the arms  61  are pivoted on the rail  141  and the slider  142  respectively. An angle between the arms  61  is θ. The second driving member  60  is moved through swinging, and the angleθ increases or decreases by the press of the arms  61  when they are moving or the recovery of spring force to move the slider  142 . 
         [0034]    When the lens cover  100  is moved from the first position to the second position, the first driving member moves the lens cover  100  to the third position from the first position first, and then the second driving member  60  takes over to move the lens cover  100  to the second position, and keep the lens cover  100  at the second position. On the contrary, when the lens cover  100  is moved from the second position to the first position, the first driving member moves the lens cover  100  to the fourth position from the second position first, and then the second driving member  60  takes over to move the lens cover  100  to the first position, and keep the lens cover  100  at the first position. 
         [0035]    The controller  40  is electrically connected to the first and the second magnetic members  31 ,  32  to supply power to the first magnetic member  31  or the second magnetic member  32  that the magnetic member  31  or  32  may generate the magnetic field to move the lens cover  100 . 
         [0036]    The detection devices  51 ,  52  are mounted on the case  10  and electrically connected to the controller  40 . The first detection device  51  detects whether the lens cover  100  has arrived the third position, and the second detection device  52  detects whether the lens cover  100  has arrived the fourth position. In the present invention, the detection devices  51 ,  52  are photo switches to sense the location of the lens cover  100 . When the lens cover  100  arrives the third position and is detected by the first detection device  51  ( FIG. 4 ), the controller  40  cuts the power supplying to the first magnetic member  31 . Accordingly, when the lens cover  100  arrives the fourth position and is detected by the second detection device  52  ( FIG. 5 ), the controller  40  cuts the power supplying to the second magnetic member  32 . 
         [0037]    As shown in  FIG. 2 ,  FIG. 4 , and  FIG. 3 , when user wants to open the lens cover  100 , which means to move the lens cover  100  from the first position to the second position, the controller  40  supplies power to the first magnetic member  31  to make it generate a magnetic field to drive the first magnetic driven member  21  on the lens cover  100 . Therefore, the lens cover  100  will be moved toward the third position, and the second driving member  60  will be compressed during the movement. When the lens cover  100  arrives the third position and the first detection device  51  detects it, the controller  40  cuts the power supplying to the first magnetic member  31  that the first magnetic member  31  no longer has power to move the lens cover  100 . At the same time, the second driving member  60  will release its spring force to move the lens cover  100  from the third position to the second position. The second driving member  60  still urges the lens cover  100  when it arrives the second position to keep the lens cover  100  at the second position. Consequently, the lens cover  100  is moved from the first position to the second position to expose the lens. 
         [0038]    As shown in  FIG. 3 ,  FIG. 5 , and  FIG. 2 , when user wants to close the lens cover  100 , which means to move the lens cover  100  from the second position to the first position, the controller  40  supplies power to the second magnetic member  32  to make it generate a magnetic field to drive the second magnetic driven member  22  on the lens cover  100 . Therefore, the lens cover  100  will be moved toward the fourth position, and the second driving member  60  will be compressed during the movement. When the lens cover  100  arrives the fourth position and the second detection device  52  detects it, the controller  40  cuts the power supplying to the second magnetic member  32  that the second magnetic member  32  no longer has power to move the lens cover  100 . At the same time, the second driving member  60  will release its spring force to move the lens cover  100  from the fourth position to the first position. The second driving member  60  still urges the lens cover  100  when it arrives the first position to keep the lens cover  100  at the first position. Consequently, the lens cover  100  is moved from the second position to the first position to cover the lens. 
         [0039]    Consequently, the present invention provides a simple lens cover module  1  to open and close the lens cover  100 . The lens cover module  1  of the present invention may function without power. User only has to move the lens cover  100  by hand to the third or the fourth position, and then the second driving member  60  will do the rest to open or close the lens cover  100 . It won&#39;t bother the user to use the image device when no power is supplied to the lens cover module  1 . 
         [0040]    In the preferred embodiment, the first driving member is not limited in using a plurality of iron plates and electromagnets, it may use the design of one or more magnet and electromagnet to move the lens cover by changing polarity of the electromagnet to attract or repulse the magnet. There still are several ways to move the lens cover except using magnetic force, such as motor and gear box, manipulation, or others. The detection device may use infrared ray switch, microswitch, or others. The torsional spring may be replaced by spring, rubber, or other elastic members. The description above is a few preferred embodiments of the present invention and the equivalence of the present invention is still in the scope of claim construction of the present invention.