Abstract:
An optical image retrieval method, which makes optical input devices work on transparent media, which method generates a light and projects it in a vertical direction. The light is directed to a light-splitter and transmitted to an image contacting surface under a transparent medium. Optical image signals retrieved on the image contacting surface are reflected to the light-splitter, and then an optical axis of the image signals is reflected to a lens by the light-splitter once or more. Finally, the lens will focus the image signals onto an image detecting element.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an optical image retrieval method, and especially relates to an optical input device for retrieving correct images from a transparent medium. 
   2. Description of Related Arts 
   A prior art mouse comprises an X-axis encoder and a Y-axis encoder with output logic sequence signals (ex. 11, 10, 00, 01). The mouse is placed on a top surface or other surfaces of a desk and moved in designated directions to place a cursor on a monitor in corresponding positions. The movement of cursor on the monitor made by the mouse adopts a principle that the X-axis and the Y-axis encoders together produce control signals to move the cursor. 
   Reference is made to  FIG. 1A  and  FIG. 1B , which illustrate cutaway views of prior art optical mice, respectively. When the prior art mouse is moved on a plane, a circuit control unit (not shown) will calculate the distance and direction of the movement of the mouse by the following steps:
     1. Light emitted from a light-emitting element  61  is projected to a first reflection surface  621  of a transparent plate  62 ;   2. The light is then reflected to a second surface  622 ;   3. The second surface  622  reflects the light onto a contact surface  64  made of a non-transparent interface through an opening of a bottom shell  63 , in which an image axis F overlaps with the contact surface  64  when the contact surface  64  is a non-transparent interface;   4. A lens  65  focuses optical image signals of the image axis F onto an image-detecting element  66 ; and   5. The optical image signals are transferred to the circuit control unit for processing.   

   An optical axis D of the projected light must be intersected at a point P of the image contacting surface  64  with an image-retrieval optical axis R and an image axis F; therefore, the image-detecting element  66  can retrieve the image on the image axis F. 
   If the image contacting surface  64  is made of a transparent medium such as glass, the image axis F does not overlap with the image contacting surface  64 . The optical axis D of the projected light may intersect with an image axis F 1  at a point M under the image contacting surface  64  (the refraction effect is not taken into account here). Meanwhile, the optical axis D and the image-retrieval optical axis R cannot intersect with the image axis F of the image contacting surface  64 , as  FIG. 1B  shows. The optical mouse therefore doesn&#39;t work on a transparent medium. 
   From another point of view, prior art mice must reflect the light emitted from the light-emitting light-emitting element  61  twice to the image contacting surface  64 , and this wastes power. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide an image retrieval method for optical mice on a transparent medium. 
   Another object of the present invention is to provide an optical mouse, which can save the power of a light source in the optical mouse. Because the light of the light source can be emitted to the transparent medium in a shortest route, the power of the light source can be saved. 
   To achieve the above objects, the present invention provides an image retrieval method for optical mice on a transparent medium, and the steps of the method are:
         1. Generating a light and projecting it in a vertical direction;   2. Directing the light to a light-splitter;   3. Splitting the light by the light-splitter and directing the split light to an image contacting surface under a transparent medium;   4. Reflecting the image signals retrieved on the image contacting surface to the light-splitter, and an image retrieval optical axis overlaps with the optical axis of the split light; and   5. Reflecting the light returned from the image contacting surface to a lens once or more by the light-splitter; the lens will focus the light to an image detecting element.       

   The method further provides:
         1. Generating a light and projecting it in a vertical direction;   2. Reflecting the light to the image contacting surface once or more by the light-splitter;   3. Reflecting the light to an image contacting surface under a transparent medium once or more by the light-splitter;   4. Reflecting the image signals retrieved on the image contacting surface to the light-splitter, and an image retrieval optical axis overlaps with the optical axis of the reflected light; and   5. Transmitting the image optical axis to a lens; the lens will focus the light of images signals to an image detecting element.       

   The above-mentioned transparent medium may be glass. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
       FIG. 1A  shows a cross-sectional view of a prior art optical mouse; 
       FIG. 1B  shows a cross-sectional view of the prior art optical mouse; 
       FIG. 2  shows a schematic view of a first embodiment according to the present invention; 
       FIG. 3  shows a schematic view of a second embodiment according to the present invention; 
       FIG. 4  shows a schematic view of a third embodiment according to the present invention; 
       FIG. 5  shows a schematic view of a fourth embodiment according to the present invention; 
       FIG. 6  shows a schematic view of a fifth embodiment according to the present invention; and 
       FIG. 7  shows a schematic view of a sixth embodiment according to the present invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Reference is made to  FIG. 2 , which shows a first embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1 , the light propagating along a vertical optical axis D, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a surface of a beam splitter  2 , where the incident light will be split into a reflected light and a transmitted light by the beam splitter  2 ;   3. Directing the transmitted light with an optical axis D 1  to an image contacting surface  31  under a transparent medium for producing an optical image signal, where the transparent medium is, for example, glass;   4. Reflecting the optical image signals from the image contacting surface  31  to an internal surface of the beam splitter  2  along an image retrieval optical axis R, where the image retrieval optical axis R overlaps with the optical axis D 1  of the transmitted light;   5. Reflecting the optical image signal with the beam splitter  2  to redirect it along an image optical axis R 1  to a lens  4 . The lens  4  will focus the light of image signals onto an image detecting element  5  (CCD or CIS); because the optical axis D 1  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be correctly retrieved by the image detecting element  5 .       

   Therefore, optical devices may operate normally on transparent media and the image detecting element  5  can retrieve the images reflected from the transparent media  3 . Further, movement and directions made by the optical mouse are calculated by control units. 
   Reference is made to  FIG. 3 , which shows a second embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1 , the light propagating along an optical axis D in a horizontal direction, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a surface of a beam splitter  2 , where the incident light will be split into a reflected light and a transmitted light by the beam splitter  2 ;   3. Directing the transmitted light with an optical axis D 1  to an image contacting surface  31  under a transparent medium for producing an optical image signal, where the transparent medium is, for example, glass;   4. Reflecting the optical image signals from the image contacting surface  31  to an internal surface of the beam splitter  2  along an image retrieval optical axis R, where the image retrieval optical axis R overlaps with the optical axis D 1  of the transmitted light;   5. Transmitting an image optical with the beam splitter  2  to redirect it along the axis R 1  to a lens  4 . The lens  4  will focus the light of optical image signals to an image detecting element  5  (CCD or CIS); because the optical axis D 1  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be correctly retrieved by the image detecting element  5 .       

   Therefore, optical devices may operate normally on transparent media  3  and the image detecting element  5  can retrieve the images reflected from the transparent media  3 . Further, movement and directions made by the optical mouse is calculated by control units. 
   The present invention further provides an optical image signals retrieval method using a beam splitter and a reflecting mirror. Reference is made to  FIG. 4 , which shows a third embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1 , the light propagating along an optical axis D in a vertical direction, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a surface of a beam splitter  6 , where the incident light will be split into a reflected light and a transmitted light by the beam splitter  6 ;   3. Directing the transmitted light along an optical axis D 1  to an image contacting surface  31  under a transparent medium, where the transparent medium is, for example, glass;   4. Reflecting optical image signals from the image contacting surface  31  to the beam splitter  6  along the an image retrieval optical axis R, where the retrieval optical axis R overlaps with the optical axis D 1  of the reflected light;   5. Reflecting the light with the beam splitter along an image optical axis R 1  to a surface of a reflecting mirror  6 ′;   6. Reflecting the light by the reflecting mirror  6 ′ along an image optical axis R 2  to a lens  4 . The lens  4  will focus the light of image signals to an image detecting element  5 ; because the optical axis D 1  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be correctly retrieved by the image detecting element  5 .       

   Therefore, optical devices may operate normally on the transparent media  3  and the image detecting element  5  can retrieve the images reflected from the transparent media  3 . Further, movement and directions made by the optical mouse are calculated by control units. 
   Reference is made to  FIG. 5 , which shows a fourth embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1  and the light propagating along an optical axis D in a vertical direction, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a surface of a reflection mirror  8 ′;   3. Directing the light reflected from the reflection mirror  8 ′ with an optical axis D 1  to a beam splitter  8 , where the incident light will be split into a reflected light and a transmitted light by the beam splitter  8 ;   4. Directing the reflected light along an optical axis D 2  to an image contacting surface  31  under a transparent medium  3 , where the transparent medium  3  may be glass;   5. Reflecting optical image signals from the image contacting surface  31  to the beam splitter  8 . An image retrieval optical axis R overlaps with the optical axis D 2  of the reflected light;   6. Transmitting the light by the beam splitter  8  with an image optical axis R 1  to a lens  4 . The lens  4  will focus the light of image signals to an image detecting element  5 ; because the optical axis D 2  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be retrieved by the image detecting element  5 .       

   Therefore, optical devices may operate normally on the transparent media  3  and the image detecting element  5  can retrieve the images reflected from the transparent media  3 . Besides, movement and directions made by the optical mouse are calculated by control units. 
   The present invention can combine a beam splitter and a reflecting mirror into one single element for providing an optical image signals retrieval method. 
   Reference is made to  FIG. 6 , which shows a fifth embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1  and an optical axis D of the light is projected in a vertical direction, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a lens unit  7 ;   3. Directing the light transmitted by the lens unit  7  with an optical axis D 1  to an image contacting surface  31  under a transparent medium  3 . The transparent medium  3  is, for example, glass;   4. Reflecting optical image signals from the image contacting surface  31  to the lens unit  7 . An image retrieval optical axis R overlaps with the optical axis D 1  of the transmitted light;   5. Directing the light reflected twice by the lens  7  with an image optical axis R 2  to a lens  4 . The lens  4  will focus the light of image signals to an image detecting element  5  (CCD or CIS); because the optical axis D 1  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be retrieved correctly by the image detecting element  5 .       

   Therefore, optical devices may operate normally on the transparent media  3  and the image detecting element  5  can retrieve the images reflected from the transparent medium  3 . Besides, movement and directions made by the optical mouse are calculated by control units. 
   Reference is made to  FIG. 7 , which shows a sixth embodiment according to the present invention. The embodiment shows an optical image signals retrieval method, and it provides following steps:
         1. Generating a light by a light-emitting element  1  and the light propagating along an optical axis D in a vertical direction, where the light-emitting element  1  is a light-emitting diode;   2. Directing the light with the optical axis D to a lens unit  9  for reflecting twice;   3. Directing the light reflected twice with an optical axis D 2  to an image contacting surface  31  under a transparent medium  3 , where the transparent medium  3  is, for example, glass;   4. Reflecting optical image signals from the image contacting surface  31  to the lens unit  9 . An image retrieval optical axis R overlaps with the optical axis D 2  of the transmitted light;   5. Transmitting the light with an image optical axis R 1  to a lens  4 . The lens  4  will focus the light of image signals to an image detecting element  5  (CCD or CIS); because the optical axis D 2  and the image retrieval optical axis R overlap and intersect with a point P of the image contacting surface  31 , images can be retrieved by the image detecting element  5 .       

   Therefore, optical devices may operate normally on the transparent media  3  and the image detecting element  5  can retrieve the images reflected from the transparent media  3 . Additionally, movement and directions made by the optical mouse are calculated by control units. 
   Furthermore, media of the above-mentioned image contacting surface  31 , such as, for example, paper, plated object, printing images, and carvings, can be set between two transparent elements, such as, for example, glass. 
   Additionally, an optical device can operate on transparent media and also on non-transparent media. 
   Although the present invention has been described with reference to the preferred embodiment therefore, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embrace within the scope of the invention as defined in the appended claims.