Abstract:
A structure of foldable optical path is suitable for use in an optical scanner with a CCD type or a type of non-contact imaging sensor. The structure of foldable optical path arranges a part of the optical path in a foldable packing device, thus the scanner is able to utilize normal lens with better depth of field and makes the scanner more compact for the convenience of operation and carrying.

Description:
BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to a structure of foldable optical path. More particularly, the present invention relates to a structure of foldable optical path inside the scanning module of a charge couple device (CCD) type optical scanner. 
     2. Description of Related Art 
     With the progress in multimedia technology, the improvement of processing of image data promoting the development of computer peripheral device such as scanner. From handheld monochrome type to present full color and high-resolution type, the scanner can produce a finer and vividly image. Today, a scanner is a widely used computer peripheral device for capturing document image and converting the document image to digital signals for computer process. 
     The optical system  100  of the conventional optical scanner as illustrated in FIG. 1 has a light source  110 , a reflection mirror set  120 , an image-formation set  130 , and an optical sensor such as a charge couple device (CCD)  140 . While performing scanning, light from the light source  110  is incident onto a document  300  putting on a light transmissible plate  200  to obtain an image light  310  by reflection or transmission. The reflection mirror set  120  comprises several reflection mirrors  121 ,  122 ,  123  and is located in an optical path of the image light  310 . The image of document  300  on the light transmissible plate  200  is directed to the reflection mirror set  120  and reflected to the image-formation set  130 , such as a lens set, by the reflection mirror set  120 . The image-formation set  130  can receive the image light  310  of the document  300  transmitted by the reflection mirror set  120 , focuses and projects the image light  310  onto the charge couple device  140 . The above-mentioned is the optical path of the image light  310  of the document  300  transmitting in the optical system  100  of the optical scanner. 
     The charge couple device mentioned above transfers the light into photoelectric current by photoelectric transformation and saves the current in a storage electrode to convert into a signal charge, then converts the charge into different potential differences. The optical scanner utilizes these different potential differences to form the different bright and dark level, then displays the image by the gray scale light. 
     Furthermore, CCD is one kind of semi-conductor IC devices and manufactured by semi-conductor process. CCD&#39;s resolution won&#39;t be affected by the manufacture easily. However, the length of the CCD is much shorter than the width of normal documents or pictures, it needs to utilize a image-formation set to reduce the scale of the image when scanning, in order to scan the full image. Thus the size of the system will be larger, and it wastes time of fabricating and adjusting. 
     Contact image sensor (CIS) is another type of linear scanner commonly used for scanning an image or a document. The image or document is captured in an electronic format for ease of storage, display, processing and transmission. Due to a modular design, the CIS is easy to assemble, light, compact and costs less to produce. FIG. 2 a  is a front view of the scanning module of a conventional contact image sensor and FIG. 2 b  is a cross-sectional view of the scanning module. As shown in FIGS. 1 a  and  1   b,  a conventional contact image sensor (CIS)  400  consists of a linear light source  404 , a self-focus lens array  401  and a sensing array  402  over a substrate board  403 . The light source  404 , the self-focus lens array  401 , the sensing array  402  and the substrate board  403  are mounted on an aluminum frame  405 . In a scanning operation, the self-focus lens array  401  reflects light coming from the original document  300  and forms an image on the sensing array  402 . The sensing array  402  converts the color or the gray step level of a line of the document  300  into electronic signals. Throughout the scanning session, the scanning surface of the scanning module  400  in constant contacts with a document platform  210 , and the document  300  is pulled forward or backward by a roller  500  for scanning. 
     The self-focus lens array  401  is constructed of a row of small-caliber radial gradient index lens, wherein the refractive index of each lens varies along the radial direction gradually, thus the lens are able to format a image. The whole lens array can format the image of one line of the original document on the sensing array in a ratio of 1:1. Compared with CCD which uses a normal image-formation set to format a image, the advantages of CIS which uses the self-focus lens array to format the image are the shorter optical path and the thinner and lighter applied system. However, the disadvantages of CIS are the depth of field is short, and the mechanical design and the control of the system need to be more precise than CCD. 
     As a conclusion, the advantages of the optical scanner which uses CIS are small-size and able to be portable, but its disadvantage is the depth of field is short, thus it&#39;s difficult to get a clear image when scanning a uneven document or picture. The advantages of the optical scanner which uses CCD is the longer depth of field, but its disadvantage is the mechanical design of the system can&#39;t be compact, thus it&#39;s not convenient to carry it. Moreover, since the document must be put on the light transmissible plate of the CCD type optical scanner while scanning, so it&#39;s not convenient in operation when scanning a thick book or large-size newspapers or magazines. Although some small-size flatbed scanners are able to put on a book or large-size newspapers or magazines to scan downward, but a user ought to hold the whole scanner during the scanning operation. Even the scanning result of the early-phase hand-held scanner is easy to be affected by operation cause it needs a user to push the scanner by hand to proceed the scanning operation. 
     SUMMARY OF INVENTION 
     Accordingly, one object of the present invention is to provide a structure of foldable optical path that can be use in the optical scanners of a CCD type or a type of non-contact imaging sensor. The structure of foldable optical path arranges part of the optical path in a foldable packing device, thus the scanner is able to utilize normal lens with better depth of field and makes the scanner more compact for the convenience of operation and carrying. A user doesn&#39;t have to push the scanner to proceed the scan operation. After the foldable packing device is folded, it&#39;s able to save the cost of package and storage because the volume of the scanner is decreased. 
     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a structure of foldable optical path for an optical scanner. The optical scanner at least having a main frame, a light transmissible plate, a light source, a reflection mirror set, an image-formation set, and an optical sensor. The light source illuminates a document to get an image light. The reflection mirror set is arranged in an optical path of the image light to direct the image light to the optical sensor. The image-formation set is arranged in the optical path between the reflection mirror set and the optical sensor. The document contacts with the light transmissible plate during scanning. The structure of foldable optical path comprises as follows. 
     A foldable packing device is coupled to the main frame by a rotation pivot axis. The foldable packing device is able to rotate from a first position, at which the scanner is under a scanning operation, to a second position, at which the foldable packing device is folded via a pivot axis. Wherein the image-formation set and the optical sensor are disposed in the interior of the foldable packing device. While the foldable packing device is at the first position, the optical path of the image light will be directed into the interior of the foldable packing device through the image-formation set to the optical sensor. While the foldable packing device is at the second position, the image-formation set and the optical sensor diverge from the optical path of the image light. 
     The invention also provides an optical scanner for scanning a document. The optical scanner comprising: a main frame, a foldable packing device, a light source, a reflection mirror set, an optical sensor, and an image-formation set. 
     The main frame has a light transmissible plate, and the document contacts with the light transmissible plate. The foldable packing device connects to the main frame, and the foldable packing device is able to rotate from a first position which the scanner is during a scanning operation to a second position which the foldable packing device is folded via a pivot axis. 
     The light source is disposed in the interior of the main frame and illuminating the document to get an image light, wherein the image light has an optical path. 
     The reflection mirror set is disposed in the optical path and in the interior of the main frame, the reflection mirror set reflects the image light. 
     The optical sensor is disposed in the interior of the foldable packing device, while the foldable packing device is at the first position, the optical path of the image light will be directed into the interior of the foldable packing device to the optical sensor, while the foldable packing device is at the second position, the optical sensor diverges from the optical path of the image light. 
     The image-formation set is disposed in the interior of the foldable packing device, while the foldable packing device is at the first position, the optical path of the image light will be directed into the interior of the foldable packing device through the image-formation set to the optical sensor, while the foldable packing device is at the second position, the image-formation set diverges from the optical path of the image light. 
     The reflection mirror set has a plurality of reflection mirrors. The reflection mirror set is able to move in the interior of the main frame during the scanning operation, and distances between the reflection mirrors are adjustable. Thus a distance from the document to the image-formation set can be fixed. The optical scanner further includes a transmission member connecting to the reflection mirror set and drives the reflection mirror set moving in the interior of the main frame. 
     The reflection mirror set and the image-formation set are able to move in the interior of the main frame during the scanning operation. Thus the distance between the reflection mirror set and the image-formation set and the distance between the optical sensor and the image-formation set are adjustable in order to maintain the same magnification of the image light through the image-formation set to the optical sensor. The optical scanner further includes a transmission member connecting to the reflection mirror set and the image-formation set, and drives the reflection mirror set and the image-formation set moving in the interior of the main frame separately. 
     The optical scanner further includes a switch disposing near the pivot axis used to detect whether the foldable packing device is at the first position or not. Moreover, a calibration chart that disposing on the light transmissible plate used to calibrate the optical scanner while power is on. 
     One major aspect of this invention is the utilization of a foldable packing device for the convenience of carrying and operation. A user don&#39;t have to push the scanner to proceed the scanning operation. 
     Another aspect of this invention is deposing part of the optical path in the interior of the foldable packing device, and the foldable packing device is able to be folded to reduce the cost of the package and storage. 
     Another aspect of this invention is utilizing of a CCD that collocates with a normal image-formation set to get a better depth of field. 
     Another aspect of this invention is deposing a switch near the pivot axis to detect the position of the foldable packing device and prevent the foldable packing device from being folded during the scanning operation or check whether the foldable is at the right position or not. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
     FIG. 1 illustrates the optical path of a conventional optical scanner; 
     FIG. 2 a  is a perspective view showing the conventional CIS; 
     FIG. 2 b  is a cross-sectional view of the conventional CIS; 
     FIG. 3 a  is a cross-sectional view of the structure of foldable optical path while the scanner in a scanning operation according to an embodiment of this invention. 
     FIG. 3 b  is a cross-sectional view of the structure of foldable optical path while the foldable packing device is folded according to an embodiment of this invention. 
     FIGS. 4 a  through  4   c  are cross-sectional views of the continuous motion of the reflection mirror set during the scanning operation according to a embodiment of this invention. 
     FIG. 5 a  is a cross-sectional view of the structure of foldable optical path while the scanner in a scanning operation according to another embodiment of this invention. 
     FIG. 5 b  is a cross-sectional view of the structure of foldable optical path while the foldable packing device is folded according to another embodiment of this invention. 
     FIG. 6 a  is a cross-sectional view of the structure of foldable optical path while the scanner in a scanning operation according to the other embodiment of this invention. 
     FIG. 6 b  is a cross-sectional view of the structure of foldable optical path while the foldable packing device is folded according to the other embodiment of this invention. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     FIG. 3 a  is a cross-sectional view showing the components of the structure of foldable optical path in a foldable packing device, according to an embodiment of this invention. As shown in FIG. 3 a,  the optical scanner includes a main frame  1000  and a foldable packing device  1400  that can serve like a handle for holding during scanning operation. That is to say, the optical scanner of the present invention is a hand-held scanner. In a scanning operation, a user holds the foldable packing device  1400  and presses the light transmissible plate  1200  onto the document  1300 , then selects the appropriate function keys  1800  (e.g. “scan” function key, “OCR” function key, or “copy” function key) deposing on the foldable packing device  1400  to proceed the scanning operation. 
     The foldable packing device  1400  is coupled to the main frame  1000  via a pivot axis  1500 , and is able to move from a first position that is suitable to proceed a scanning operation (as shown in FIG. 3 a ) to a second position that the foldable packing device  1400  is folded (as shown in FIG. 3 b ) by rotating. A switch  1600  which is able to detect the position of the foldable packing device  1400  is deposed near the pivot axis  1500  to make sure the foldable packing device  1400  is at the first position. If the foldable packing device  1400  is not at the first position exactly, the optical scanner won&#39;t start to scan. If the foldable packing device  1400  is folded during the scanning operation, the optical scanner will stop scanning. 
     Similarly, the optical system  1100  of the optical scanner of the present invention has a light source  1110 , a reflection mirror set  1120 , a image-formation set  1130 , and an optical sensor  1140 , wherein the optical sensor of the present invention is CCD. While performing scanning, light from the light source  1110  is incident onto a document  1300  putting on a light transmissible plate  1200  to obtain an image light  1310  by reflection or transmission. The reflection mirror set  1120  comprises several reflection mirrors  1121 ,  1122 ,  1123 , and  1124  and is located in an optical path of the image light  1310 . The image light  1310  of document  1300  on the light transmissible plate  1200  is directed to the reflection mirror set  1120  and reflected to the image-formation set  1130  by the reflection mirror set  1120 . The image-formation set  1130  can receive the image light  1310  of the document  1300  transmitted by the reflection mirror set  1120  and display the image light  1310  on the charge couple device  1140 . The above-mentioned is the optical path of the image light  1310  of the document  1300  transmitting in the optical system  1100  of the optical scanner. 
     As shown in FIG. 3 a,  the image-formation set and the CCD  1140  are deposed in the interior of the foldable packing device  1400 . While the foldable packing device  1400  is at the first position, the optical path of the image light  1310  will be directed into the interior of the foldable packing device  1400  through the image-formation set  1130  to the CCD  1140 , and while the foldable packing device  1400  is at the second position, the image-formation set  1130  and the optical sensor  1140  diverge from the optical path of the image light  1310 . In another word, the structure of foldable optical path of the present invention is able to fold the later half of the optical path for the convenience of the mechanical design, and make the optical scanner more compact for the convenience of carrying or storage. 
     In the optical system of conventional optical scanner, the whole optical system moves together during the scanning operation, but in the present invention, only reflection mirror set  1120  (such as three reflection mirrors  1121 , 1122 , and  1123  in this embodiment) and light source  1110  are moving during the scanning operation as shown in FIG. 3 a.  In order to avoid the distance between the reflection mirror set  1120  and the image-formation set  1130  (in this case shown in FIG. 3 a,  the distance is between the mirror  1123  and  1124 ) being changed (larger) during the scanning operation thus cause the image light  1310  can&#39;t display on the CCD  1140  through the image-formation set  1130 , the present invention utilize a movable reflection mirror set. That is, the distances between each reflection mirror  1121 , 1122 , 1123 , and  1124  are adjustable, thus the present is able to fix the length of the optical path of the image light  1310  from the document  1300  through the reflection mirror set  1120  to the image-formation set  1130 . 
     FIGS. 4 a ˜ 4   c  illustrate the continuous motion of the movable reflection mirror set. The whole reflection mirror set is moving toward right and far away from the image-formation set  1130  during the scanning operation. In the mean time, the reflection mirror  1121  is moving close to the reflection mirror  1122 , thus the length of the optical path of the image light from the document through the reflection mirror set to the image-formation set is able to be fixed. The motion of the movable reflection mirror set can be controlled by a CPU. The optical scanner further concludes a transmission member  1900  connecting to the reflection mirror set  1120 . The transmission member  1900  can drive the reflection mirror set  1120  moving in the interior of the main frame  1900 . Moreover, the transmission member  1900  may conclude a motor and transmission devices such as a transmission gear set and a belt. 
     Furthermore, because the later half of the optical path may be not in the correct position when folding or opening the foldable packing device every time, the present further provides a calibration chart  1700  on one end of the light transmissible plate  1200  where the optical system  1100  initial to scan the document  1300 . Every time when the optical scanner connects to a PC or turns on its power, it will scan the calibration chart  1700  first to get arguments and compensate the deviating in left or right, the shift in front and rear, or the magnification. Moreover, while the optical scanner is power on, if the switch  1600  detects that the foldable packing device  1400  is folded and reopened, the CPU will command the scanner rescan the calibration chart  1700  to renew the arguments. 
     The formation of the foldable packing device  1400  is not limited to be deposed on the left top side of the main frame  1000  and folded toward right as shown in FIGS. 3 a  and  3   b.  The foldable packing device  1400  can be deposed on any place of the main frame  1000  and folded toward any direction. For example, as shown in FIGS. 5 a  and  5   b,  the foldable packing device  1400  is deposed at right side of the main frame  1000  and folded downward; or as shown in FIGS. 6 a  and  6   b,  the foldable packing device  1400  is deposed on top of the main frame  1000  and folded downward directly, wherein the material of the cover of the connection portion between the foldable packing device  1400  and the main frame  1000  is soft and able to change its shape. 
     Consequently, it will be apparent to those skilled in the art that various modifications and variations can be made to the formation of the foldable packing device of the present invention without departing from the scope or spirit of the invention. 
     In conclusion, major advantages of this invention include: 
     1. providing a foldable packing device for the convenience of carrying and operation, a user don&#39;t have to push the scanner to proceed the scanning operation. 
     2. deposing part of the optical path in the interior of the foldable packing device, and the foldable packing device is able to be folded to reduce the cost of the package and storage. 
     3. utilizing of a CCD that collocates with a normal image-formation set to get a better depth of field. 
     4. deposing a switch near the pivot axis to detect the position of the foldable packing device and prevent the foldable packing device from being folded during the scanning operation or check whether the foldable is at the right position or not. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.