Abstract:
A scanner, including a contact image sensor module and an elasticity-providing element, is provided. When scanning, the elasticity-providing element is capable of avoiding vertical shift of contact image sensor module resulting from mechanical friction or other unexpected. Therefore, the contact image sensor module can retrieve clear images all the time.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims priority to Taiwan Patent application No. 092117092 filed on Jun. 24, 2003.  
         FIELD OF INVENTION  
         [0002]    The present invention relates to a scanner, in particular a scanner including an elastic support element.  
         BACKGROUND OF THE INVENTION  
         [0003]    Contact image sensor (CIS) scanners are popular computer peripheral devices. They are used for scanning documents or pictures. The conversion results are stored in a digital format or further processed by computers.  
           [0004]    The CIS module usually includes a light source, a lens for focusing, an image sensor and a carriage. Since the focal distance of the CIS module is merely 0.3 mm, only documents or pictures within this distance will be clearly scanned. Once the object is outside that range, the scanned image will be blurred. Please refer to FIG. 1. Because of the strict limit, the image sensor  104  may not be able to retrieve clear images if there is a vertical movement brought about by the unevenness of guiding shaft  200  or other mechanical reasons when the carriage  108  moves along the guiding shaft  200 . In order to solve this problem, it is known in the conventional techniques that an elastic element  202  is disposed between the carriage  108  and the image sensor  104  to absorb any forces that cause undesirable movement.  
           [0005]    However, the limited space between the carriage  108  and the image sensor  104  restricts the size and the elasticity of the elastic element  202 , which in turn limit the lifetime of the CIS scanner.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention provides a CIS scanner including a window glass, a contact image sensor module, a carriage, a guiding shaft and a force-providing element. The documents or the pictures are placed on the window glass. The contact image sensor module is located below the window glass for scanning the image on the documents or the pictures. The carriage carries the contact image sensor module and has at least a hole. The guiding shaft is located below the carriage and movably connected to the carriage for horizontally guiding the carriage in use. The force-providing element includes an elastic part passing through the hole and touches against the contact image sensor module. The force-providing element provides a force making the contact image sensor module maintain a constant distance from the window glass to avoid retrieving blurry images caused by any undesirable movement while the contact image sensor module moves.  
           [0007]    The CIS scanner of the present invention further includes a smooth element, positioned between the contact image sensor module and the window glass, for facilitating movement of the CIS module.  
           [0008]    The force-providing element may include a helical unit movably sleeved into the guiding shaft. At least an elastic part is an extension unit from one end of the helical unit for supporting the contact image sensor module.  
           [0009]    The force-providing element may further include a spacing element sleeved into the guiding shaft for facilitating movement of the guiding shaft along an axle direction of the helical unit.  
           [0010]    There are still many other variants for the force-providing element. For example, the force-providing element may include an arc-shaped structure for seating on the guiding shaft. The elastic part may be a resilient element for supporting the contact image sensor module. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a cross-sectional view of a conventional CIS scanner;  
         [0012]    [0012]FIG. 2 is a side view of the first embodiment of the present invention;  
         [0013]    [0013]FIG. 3A is a perspective view of the force-providing element of the first embodiment of the present invention;  
         [0014]    [0014]FIG. 3B is a perspective view of the force-providing element of the first embodiment of the present invention, the force-providing element including a spacing element;  
         [0015]    [0015]FIG. 4 is an explosive view of the first embodiment of the present invention;  
         [0016]    [0016]FIG. 5 is an explosive view of the second embodiment of the present invention;  
         [0017]    [0017]FIG. 6 is a perspective view of the force-providing element of the second embodiment of the present invention;  
         [0018]    [0018]FIG. 7 is a side view of the third embodiment of the present invention; and  
         [0019]    [0019]FIG. 8 is a perspective view of the force-providing element of the third embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0020]    The CIS scanner of the present invention utilizes a force-providing element to maintain the contact image sensor module at a constant distance from the window glass while the contact image sensor module moves. The force-providing element may include a helical unit movably sleeved into the guiding shaft. An elastic part is an extension unit from one end of the helical unit for supporting the contact image sensor module.  
         [0021]    The first embodiment of the present invention, shown in FIG. 2, includes a window glass  300 , a contact image sensor module  302 , a carriage  304 , a guiding shaft  306 , two smooth elements  308 , a guiding element  310  and a force-providing element  312   a . The documents or the pictures  314  are placed on the window glass  300 . The contact image sensor module  302  including a contact image sensor (not shown) is located below the window glass  300  for retrieving the images on the documents or the pictures  314 . The carriage  304  carries and accommodates the contact image sensor module  302  and has two holes  316  and  318 . The guiding shaft  306  is located below the carriage  304  for guiding the movement of the carriage  304 . The two smooth elements are positioned between the carriage  304  and the window glass  300  for facilitating the movement of the CIS module. The guiding element  310  is positioned at the bottom of the carriage  304  as a connecting interface for movably accommodating the guiding shaft  306 .  
         [0022]    The force-providing element  312   a  in the first embodiment shown in FIG. 2 is a torsion spring. Torsion spring  312   a  includes a helical unit  400 , two extension units  402  and  404  and two fixed units  408  and  410 , as illustrated in FIG. 3A. The inner diameter of the helical unit  400  is slightly larger than that of the guiding shaft  306  so that the guiding shaft  306  can be movably sleeved into the helical unit  400 . Two extension units  402  and  404  each pass through the holes  316  and  318  in FIG. 2 to support the contact image sensor module  302  by using two fixed units  408  and  410 . Even though the horizontal movement of the carriage  304  may cause the carriage  304  and the contact image sensor module  302  to vibrate, the elastic force provided by the two extension units  402  and  404  along the direction shown in FIG. 2 maintains the contact image sensor module  302  at a constant distance from the window glass  300  at all times to make sure the object to be scanned is within the limited focal distance.  
         [0023]    The force-providing element, shown in FIG. 3B, may further include a spacing element  406  in the shape of a hollow cylinder. The spacing element  406  is located between the guiding shaft  306  and the helical unit  400  for facilitating the movement of the guiding shaft  306  along the axle direction of the helical unit  400 .  
         [0024]    [0024]FIG. 4 is an explosive view of the first embodiment that includes a spacing element  406  of the present invention. The structure of the first embodiment can be more clearly understood by referring to FIG. 2, FIG. 3A and FIG. 3B.  
         [0025]    The present invention also provides another CIS scanner whose force-providing element includes an arc-shaped structure and an elastic part. The arc-shaped structure movably sits on the guiding shaft and the elastic part extends from an end of the helical unit for supporting the contact image sensor module to maintain the contact image sensor module at a constant distance from the window glass while the contact image sensor module moves.  
         [0026]    The second embodiment of the present invention is shown in FIG. 5. The carriage  304  includes a hole  600  that allows a force-providing element  312   b  to pass through for supporting the contact image sensor module  302 . The force-providing element  312   b  in the second embodiment shown in FIG. 6 includes an arc-shaped structure  700  and a resilient element  702 . The curvature of the arc-shaped structure  700  corresponds to that of the guiding shaft  306 . The resilient element  702  passes through the hole  600  for supporting the contact image sensor module  302 . Even though the horizontal movement of the carriage  304  may cause the carriage  304  and contact image sensor module  302  to vibrate, the elastic force provided by the resilient element  702  maintains the contact image sensor module  302  at a constant distance from the window glass  300  (not shown in FIG. 5) at all times to ensure the image to be scanned is within the limited focal distance. Unless otherwise mentioned, other components in the second embodiment are similar to those in the first embodiment.  
         [0027]    The third embodiment of the present invention is shown in FIG. 7. The carriage  304  includes two holes  800  and  802 . The force-providing element  312   c  shown in FIG. 8 includes an arc-shaped structure  804  and two springs  806  and  808 . Springs  806  and  808  respectively pass through holes  800  and  802  for supporting the contact image sensor module  302 . Similarly, the elastic force provided by springs  806  and  808 , in the direction shown in the figure, maintains the contact image sensor module  302  at a constant distance from the window glass  300  at all times when the carriage  304  moves horizontally. Unless otherwise mentioned, other components in the third embodiment are similar to those in the first embodiment.  
         [0028]    By means of the detailed descriptions of what is presently considered to be the most practical and preferred embodiments of the subject invention, it is the expectation that the features and the gist thereof are plainly revealed. Nevertheless, these above-mentioned illustrations are not intended to be construed in a limiting sense. Instead, it should be well understood that any analogous variation and equivalent arrangement is to be protected and that the interpretation of the scope of the subject invention would therefore as much as broadly apply.