Abstract:
An optical reading device of a scanning apparatus includes two light sources and a movable lens. The first light source emits a first light when the optical reading device is operated in a flatbed scanning mode. The second light source emits a second light when the optical reading device is operated in a sheetfed scanning mode. The movable mirror is selected to allow for passing the first light without being obstructed by the movable mirror in the flatbed scanning mode or allow for reflecting the second light coming from the second mirror in the sheetfed scanning mode. Due to the special design, the overall volume of the scanning module is reduced.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an optical reading device of a scanning apparatus, and more particularly to an optical reading device having dual light sources and a light path adjustable mechanism.  
       BACKGROUND OF THE INVENTION  
       [0002]     Image scanners are widely used for scanning documents. Image scanners are generally classified as two major types: flatbed scanners and sheetfed scanners. In the flatbed scanner, a document is firstly placed on the glass platform, and then the optical reading device is driven by a driving device (not shown) to scan the document. For a purpose of successively scanning many paper sheets at a time, an automatic paper feeder (ADF), which is usually used in the sheetfed scanner, is integrated into the flatbed scanner. Under this circumstance, the flatbed scanner having the automatic paper feeder (ADF) is capable of performing dual-mode scanning operations. For clarification, such a scanner is referred as a dual-mode scanner hereinafter. Referring to  FIG. 1A  and  FIG. 1B , a dual-mode scanner capable of respectively scanning a single paper sheet in the flatbed scanning mode and a lot of paper sheets in the sheetfed scanning mode is illustrated.  
         [0003]     As shown in  FIG. 1A  and  FIG. 1B , the dual-mode scanner  1  has an optical reading device  10  similar to that used in the general flatbed scanner. During the process of performing the sheetfed scanning operation, the optical reading device  10  should be moved under the scanning window  11  such that the light emitted from the optical reading device  10  can be projected onto the scanning window  11 . Therefore, it is required to reserve an additional operative space  12  for accommodating the optical reading device  10  when the dual-mode scanner  1  is operated in the sheetfed scanning mode. Likewise, the overall volume of the scanner  1  is increased.  
         [0004]     In views of the above-described disadvantages of the prior art, the applicant keeps on carving unflaggingly to develop an improved optical reading device of a scanning apparatus according to the present invention through wholehearted experience and research.  
       SUMMARY OF THE INVENTION  
       [0005]     It is an object of the present invention to provide an optical reading device of a scanning apparatus, in which the operative space for accommodating the optical reading device when the dual-mode scanner is operated in the sheetfed scanning mode is reduced and thus the overall volume of the scanner is also reduced.  
         [0006]     In accordance with an aspect of the present invention, there is provided an optical reading device of a scanning apparatus. The optical reading device comprises a housing, a first light source, a second light source, a first mirror, a second mirror, a movable mirror, a mirror set, a lens set and an optical sensing module. The housing has a first slot and a second slot in a surface thereof. The first light source is disposed beside the first slot for providing a first light when the optical reading device is operated in a flatbed scanning mode. The second light source is disposed beside the second slot for providing a second light when the optical reading device is operated in a sheetfed scanning mode. The first mirror is disposed under the first slot for reflecting the first light entered via the first slot. The second mirror is disposed under the second slot for reflecting the second light entered via the second slot. The movable mirror is selected to allow for passing the first light without being obstructed by the movable mirror in the flatbed scanning mode or allow for reflecting the second light coming from the second mirror in the sheetfed scanning mode. The mirror set successively reflects the first light coming from the first mirror in the flatbed scanning mode and successively reflects the second light coming from the movable mirror. The lens set focuses the first light coming from the mirror set in the flatbed scanning mode and focuses the second light coming from the mirror set in the sheetfed scanning mode. The optical sensing module receives the first light and the second light and converts the first light and the second light into electrical signals. The first light source, the second light source, the first mirror, the second mirror, the movable mirror, the mirror set, a lens set and the optical sensing module are contained inside the housing.  
         [0007]     In an embodiment, the first mirror and the second mirror are symmetrically arranged at opposite sides of an image plane.  
         [0008]     In an embodiment, the reflective surface of the movable mirror is aligned with the image plane when the optical reading device is operated in the sheetfed scanning mode.  
         [0009]     In an embodiment, the optical reading device further comprises a movable light shield plate selectively to be moved under the first slot for shielding the first slot when the optical reading device is operated in the sheetfed scanning mode or under the second slot for shielding the second slot when the optical reading device is operated in the flatbed scanning mode.  
         [0010]     The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1A  and  FIG. 1B  are schematic views illustrating a dual-mode scanner selectively operated in a flatbed scanning mode or a sheetfed scanning mode according to prior art, respectively;  
         [0012]      FIG. 2A  and  FIG. 2B  are schematic views illustrating a dual-mode scanner selectively operated in a flatbed scanning mode or a sheetfed scanning mode according to a preferred embodiment of the present invention, respectively; and  
         [0013]      FIG. 3A  and  FIG. 3B  are schematic views illustrating the relative locations of the mirrors and the movable mirror when the dual-mode scanner is operated in the flatbed scanning mode and the sheetfed scanning mode, respectively. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]     Referring to  FIG. 2A  and  FIG. 2B , a dual-mode scanner for respectively scanning a single paper sheet in the flatbed scanning mode and a lot of paper sheets in the sheetfed scanning mode according to a preferred embodiment of the present invention is illustrated. The dual-mode scanner of the present invention is distinguished by the optical reading device and the optical path adjustable mechanism.  
         [0015]     As shown in  FIG. 2A  and  FIG. 2B , the optical reading device  20  of the dual-mode scanner  2  comprises light sources  22 A and  22 B, mirrors  23 A and  23 B, a movable mirror  24 , a mirror set  25 , a lens set  26  and an optical sensing module  27 , which are contained inside a housing  28 . The housing  28  has two slots  28 A and  28 B disposed above the light sources  22 A and  22 B, respectively. When the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the light emitted from the light source  22 A is projected onto the document  3 A to be scanned, and the light reflected from the scanned document  3 A enters the slot  28 A of the housing  28 . Whereas, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the light emitted from the light source  22 B is projected onto the documents  3 B to be scanned, and the light reflected from the scanned document  3 B enters the slot  28 B of the housing  28 .  
         [0016]     Due to the slots  28 A and  28 B in the housing  28  of the optical reading device  20 , the optical reading device  20  only needs to be slightly moved toward the right side when the dual-mode scanner  2  is switched from operation in the flatbed scanning mode to the sheetfed scanning mode, so that the slot  28 B is moved to the location just below the scanning window  28 . Alternatively, if the location of the slot  28 B is just below the scanning window  21  according to the manufacture&#39;s design, the optical reading device  20  needs not be moved rightwards when the dual-mode scanner  2  is switched from operation in the flatbed scanning mode to the sheetfed scanning mode. Under this circumstance, it is not required to reserve an additional operative space to accommodate the optical reading device  20  when the dual-mode scanner  2  is operated in the sheetfed scanning mode.  
         [0017]     In some embodiments of the optical reading device  20 , each of the light sources  22 A and  22 B includes two lamps or a single lamp. When the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the light source  22 A is turned on but the light source  22 B is turned off. Whereas, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the light source  22 B is turned on but the light source  22 A is turned off.  
         [0018]     Please refer to  FIG. 2A  and  FIG. 2B  again. The optical reading device  20  further comprises a movable light shield plate  29  selectively to be moved under the slot  28 A or  28 B. When the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the light shield plate  29  is moved to the location under the slot  28 B so as to prevent the external stray light from entering the slot  28 B of the housing  28 . Whereas, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the light shield plate  29  is moved to the location under the slot  28 A so as to prevent the external stray light from entering the slot  28 A of the housing  28 .  
         [0019]     Please refer to  FIG. 2A  and  FIG. 2B  again. The optical reading device  20  further comprises two mirrors  23 A and  23 B under the slots  28 A and  28 B, respectively. When the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the light emitted from the light source  22 A is projected onto the document  3 A to be scanned. In the flatbed scanning mode, the light reflected from the scanned document  3 A then enters the slot  28 A and is successively reflected by the mirror  23 A and the mirror set  25 . Whereas, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the light emitted from the light source  22 B is projected onto the documents  3 B to be scanned. In the sheetfed scanning mode, the light reflected from the scanned documents  3 B then enters the slot  28 B and is successively reflected by the mirror  23 B, a movable mirror  24  and the mirror set  25 . It is noted that the tilt angle of the movable mirror  24  of the optical reading device  20  is adjustable depending on the scanning modes. For example, when the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the tilt angle of the movable mirror  24  is small or zero. Under this circumstance, the light reflected from the mirror  23 A would be transmitted to the mirror set  25  without being obstructed by the movable mirror  24 . In contrast, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the movable mirror  24  is substantially adjusted to a vertical position, and thus the light reflected from the mirror  23 B would be successively reflected by the movable mirror  24  and the mirror set  25 .  
         [0020]     The optical paths of the optical reading device  20  are also illustrated with reference to  FIG. 2A  and  FIG. 2B . When the dual-mode scanner  2  is operated in the flatbed scanning mode as shown in  FIG. 2A , the light emitted from the light source  22 A is projected onto the document  3 A to be scanned. Then, the light reflected from the scanned document  3 A enters the slot  28 A, is successively reflected by the mirror  23 A and the mirror set  25 , and focused by the lens set  26 . The focused light is then imaged onto the optical sensing module  27  such as a charge couple device (CCD) so as to convert the optical signals into electrical signals. In contrast, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B , the light emitted from the light source  22 B is projected onto the documents  3 B to be scanned. Then, the light reflected from the scanned document  3 B enters the slot  28 B, is successively reflected by the mirror  23 B, the movable mirror  24  and the mirror set  25 , and focused by the lens set  26 . Afterwards, the focused light is imaged onto the optical sensing module  27  so as to convert the optical signals into electrical signals.  
         [0021]     Referring to  FIG. 3A  and  FIG. 3B , the relative locations of the mirror  23 A, the mirror  23 B and the movable mirror  24  inside the housing  28  of the optical reading device  20  are illustrated. It is preferred that the mirrors  23 A and  23 B are symmetrically arranged at opposite sides of an image plane  5 . In such manner, when the dual-mode scanner  2  is operated in the sheetfed scanning mode as shown in  FIG. 2B  and the movable mirror  24  is substantially adjusted to a vertical position, the reflective surface of the movable mirror  24  is aligned with the image plane  5 . Accordingly, the distance of the optical path in the flatbed scanning mode is substantially identical to that in the sheetfed scanning mode.  
         [0022]     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.