Abstract:
An optical projection device includes a laser engine, a first wave plate and a lens. The laser engine provides light. The first wave plate changes a light phase. The lens focuses light. A projecting method of an optical projection device includes providing a light including a first P polarized light, a first S polarized light, and a second S polarized light, and projecting light through a wave plate on a screen, wherein the wave plate moves in a direction perpendicular to light. A projecting method of an optical projection device includes providing light including a first P polarized light, a first S polarized light, and a second S polarized light, and projecting light through a wave plate on a screen, wherein the wave plate rotates around an axis parallel to a projecting direction of light.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Patent Application No. 098126152, filed on Aug. 4, 2009, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical projection device and a projecting method thereof, and more particularly, to an optical projection device and a projecting method thereof utilizing a movable wave plate or a rotatable wave plate to equalize the laser energy and preventing interference speckle on screens. 
     2. Description of the Related Art 
       FIG. 1  is a schematic view of a conventional optical projection device. The conventional optical projection device  100  comprises a lens  11  and a laser engine  12 . The laser engine  12  generates light  13 . After passing through the lens  11 , an image is projected on the screen  10 . 
     However, in the conventional optical projection device  100 , the path of light  13  from the laser engine  12  to the screen  10  is not changed. Thus, the interference position of light is not changed, that is, the interference speckle is also not changed. Thus, the interference speckle of the conventional optical projection device  100  is very conspicuous. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an optical projection device. The optical projection device includes a laser engine, a first wave plate, a screen and a lens. The laser engine generates light. The first wave plate changes a light phase and the lens focuses light on the screen. 
     Note that the lens is disposed between the screen and the first wave plate. 
     Note that the first wave plate is disposed between the screen and the lens. 
     Note that light comprises a first P polarized light, a first S polarized light, and a second S polarized light. After light passes through the first wave plate, the first P polarized light is transformed to a third S polarized light, the first S polarized light is transformed to a second P polarized light, and the second S polarized light is transformed to a third P polarized light. 
     Note that the laser engine comprises an X-Prism, a second wave plate, a first polarized light generator, a second polarized light generator, and a third polarized light generator. The first polarized light generator generates a fourth S polarized light to pass through the second wave plate to generate a fourth P polarized light. The second polarized light generator generates a fifth S polarized light. The third polarized light generator generates a sixth S polarized light. The fourth P polarized light, the fifth S polarized light and the sixth S polarized light are integrated into light by the X-Prism. 
     Note that the first polarized light generator comprises a green laser source, a first polarized spectroscope and a first reflecting panel. The green laser source generates a green laser to pass through the first polarized spectroscope to generate a fifth P polarized light. The fifth P polarized light is reflected by the first reflecting panel to generate a seventh S polarized light. The seventh S polarized light is reflected by the first polarized spectroscope to generate the fourth S polarized light. 
     Note that the second polarized light generator comprises a blue laser source, a second polarized spectroscope and a second reflecting panel. The blue laser source generates a blue laser to pass through the second polarized spectroscope to generate a sixth P polarized light. The sixth P polarized light is reflected by the second reflecting panel to generate an eighth S polarized light. The eighth S polarized light is reflected by the second polarized spectroscope to generate the fifth S polarized light. 
     Note that the third polarized light generator comprises a red laser source, a third polarized spectroscope and a third reflecting panel. The red laser source generates a red laser to pass through the third polarized spectroscope to generate a seventh P polarized light. The seventh P polarized light is reflected by the third reflecting panel to generate an ninth S polarized light. The ninth S polarized light is reflected by the third polarized spectroscope to generate the sixth S polarized light. 
     The present invention provides a projecting method of an optical projection device. The steps comprises: providing light including a first P polarized light, a first S polarized light, and a second S polarized light; projecting light through a wave plate on a screen; and moving the wave plate in a direction perpendicular to light. 
     Note that light passes through a lens and then passes through the wave plate. 
     Note that light passes through the wave plate, then passes through a lens, and then projects on the screen. 
     The present invention provides a projecting method of an optical projection device. The steps comprises: providing light including a first P polarized light, a first S polarized light, and a second S polarized light; projecting light through a wave plate on a screen; and rotating the wave plate around an axle parallel to a projecting direction of light. 
     Note that light passes through a lens and then passes through the wave plate. 
     Note that light passes through the wave plate, then passes through a lens, and then projects on the screen. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a conventional optical projection device; 
         FIG. 2  is a schematic view of an optical projection device of an embodiment of the invention; 
         FIG. 3  is a block diagram of an optical projection device of an embodiment of the invention; 
         FIG. 4  is a schematic view of an optical projection device of another embodiment of the invention; 
         FIG. 5  is a block diagram of an optical projection device of another embodiment of the invention; 
         FIG. 6  is a schematic view of an optical projection device of another embodiment of the invention; 
         FIG. 7  is a block diagram of an optical projection device of another embodiment of the invention; 
         FIG. 8  is a schematic view of an optical projection device of another embodiment of the invention; and 
         FIG. 9  is a block diagram of an optical projection device of another embodiment of the invention. 
     
    
    
     The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  is a schematic view of an optical projection device of an embodiment of the invention. The optical projection device  200  comprises a lens  21 , a first wave plate  22  and a laser engine  23 . The laser engine  23  generates light  24  to pass through the first wave plate  22  and the lens  21 , forming into an image on a screen  20 . The first wave plate  22  moves up and down by a motor (not shown) during operation to equalize the laser energy and prevent interference speckles on the screen  20 . Referring to  FIG. 3 , the laser engine  23  comprises an X-prism  231 , a first polarized light generator  232 , a second polarized light generator  233 , a third polarized light generator  234  and a second wave plate  235 . The elements of the optical projection device  200  are described as follows. 
     The first polarized light generator  232  comprises a green laser source  2321  to generate a green laser L G  to pass through a first polarized spectroscope  2322  to generate a P polarized light P 5  reflected by a first reflecting panel  2323  to generate an S polarized light S 7 . The S polarized light S 7  is reflected by the first polarized spectroscope  2322  to generate a P polarized light P 4 . The P polarized light P 4  is transmitted from the first polarized light generator  232  to the second wave plate  235 , and then passes through the second wave plate  235  to transform into a P polarized light P 4  and then enter the X-prism  231 . 
     The second polarized light generator  233  comprises a blue laser source  2331  to generate a blue laser L B  to pass through a second polarized spectroscope  2332  to generate a P polarized light P 6  reflected by a second reflecting panel  2333  to generate an S polarized light S 8 . The S polarized light S 8  is reflected by the second polarized spectroscope  2332  to generate an S polarized light S 5 . The S polarized light S 5  is transmitted from the second polarized light generator  233  to the X-prism  231 , and enters the X-prism  231 . 
     The third polarized light generator  234  comprises a red laser source  2341  to generate a red laser L R  to pass through a third polarized spectroscope  2342  to generate a P polarized light P 7  reflected by a third reflecting panel  2343  to generate an S polarized light S 9 . The S polarized light S 9  is reflected by the third polarized spectroscope  2342  to generate an S polarized light S 6 . The S polarized light S 6  is transmitted from the third polarized light generator  234  to the X-prism  231 , and enters the X-prism  231 . 
     The X-prism  231  integrates the P polarized light P 4  generated by the first polarized light generator  232 , the S polarized light S 5  generated by the second polarized light generator  233  and the S polarized light S 6  generated by the third polarized light generator  234  into light to radiate. Light  24  comprises a P polarized light P 1 , an S polarized light S 1 , and an S polarized light S 2 . 
     After light  24  radiated by the laser engine  23  passes through the first wave plate  22 , the P polarized light P 1  is transformed to an S polarized light S 3 , the S polarized light S 1  is transformed to a P polarized light P 2 , and the S polarized light S 2  is transformed to a P polarized light P 3 . Finally, light  24  is focused on the screen  20  by the lens  21 . 
     During operation, the optical projection device  200  utilizes the first wave plate  22  to quickly move to change the angle between the light  24  and the axle of the first wave plate  22 , to change the direction of the electric field when light  24  moves. Thus, laser energy is equalized following variations of the interference position. Further, the interference speckle on the screen  20  is eliminated. Moreover, providing the laser source can reduce the quantity of the optical elements and the volume of the projector. Cost is decreased and the efficiency of production and assembly is increased. 
       FIG. 4  is a schematic view of an optical projection device of another embodiment of the invention. The optical projection device  400  comprises a lens  21 , a first wave plate  42  and a laser engine  23 . The laser engine  23  generates light  24  to pass through the first wave plate  42  and the lens  21 , forming into an image on a screen  20 . The first wave plate  42  rotates around an axle parallel to a projecting direction of light  24  by a motor (not shown) to equalize the laser energy and delete the interference speckle on the screen  20 . Referring to  FIG. 5 , the laser engine  23  comprises an X-prism  231 , a first polarized light generator  232 , a second polarized light generator  233 , a third polarized light generator  234  and a second wave plate  235 . The elements of the laser engine  23  are described as follows. 
     The first polarized light generator  232  comprises a green laser source  2321  to generate a green laser L G  to pass through a first polarized spectroscope  2322  to generate a P polarized light P 5  reflected by a first reflecting panel  2323  to generate an S polarized light S 7 . The S polarized light S 7  is reflected by the first polarized spectroscope  2322  to generate a P polarized light P 4 . The P polarized light P 4  is transmitted from the first polarized light generator  232  to the second wave plate  235 , and then passes through the second wave plate  235  to transform into a P polarized light P 4  and then enter the X-prism  231 . 
     The second polarized light generator  233  comprises a blue laser source  2331  to generate a blue laser L B  to pass through a second polarized spectroscope  2332  to generate a P polarized light P 6  reflected by a second reflecting panel  2333  to generate an S polarized light S 8 . The S polarized light S 8  is reflected by the second polarized spectroscope  2332  to generate an S polarized light S 5 . The S polarized light S 5  is transmitted from the second polarized light generator  233  to the X-prism  231 , and enters the X-prism  231 . 
     The third polarized light generator  234  comprises a red laser source  2341  to generate a red laser L R  to pass through a third polarized spectroscope  2342  to generate a P polarized light P 7  reflected by a third reflecting panel  2343  to generate an S polarized light S 9 . The S polarized light S 9  is reflected by the third polarized spectroscope  2342  to generate an S polarized light S 6 . The S polarized light S 6  is transmitted from the third polarized light generator  234  to the X-prism  231 , and enters the X-prism  231 . 
     The X-prism  231  integrates the P polarized light P 4  generated by the first polarized light generator  232 , the S polarized light S 5  generated by the second polarized light generator  233  and the S polarized light S 6  generated by the third polarized light generator  234  into light to radiate. Light  24  comprises a P polarized light P 1 , an S polarized light S 1 , and an S polarized light S 2 . 
     After light  24  radiated by the laser engine  23  passes through the first wave plate  22 , the P polarized light P 1  is transformed to an S polarized light S 3 , the S polarized light S 1  is transformed to a P polarized light P 2 , and the S polarized light S 2  is transformed to a P polarized light P 3 . Finally, light  24  is focused on the screen  20  by the lens  21 . 
     During operation, the optical projection device  400  utilizes the first wave plate  42  to quickly move to change the angle between the light  24  and the axle of the first wave plate  42 , to change the direction of the electric field when light  24  moves. Thus, laser energy is equalized following variations of the interference position. Further, the interference speckle on the screen  20  is eliminated. Moreover, providing the laser source can reduce the quantity of the optical elements and the volume of the projector. Cost is decreased and the efficiency of production and assembly is increased. 
       FIG. 6  is a schematic view of an optical projection device of another embodiment of the invention. The optical projection device  600  comprises a lens  21 , a first wave plate  62  and a laser engine  23 . The laser engine  23  generates light  24  to pass through the first wave plate  62  and the lens  21 , forming into an image on a screen  20 . The first wave plate  62  moves up and down by a motor (not shown) during operation to equalize the laser energy and prevent interference speckles on the screen  20 . Referring to  FIG. 7 , the laser engine  23  comprises an X-prism  231 , a first polarized light generator  232 , a second polarized light generator  233 , a third polarized light generator  234  and a second wave plate  235 . The elements of the laser engine  23  are described as follows. 
     The first polarized light generator  232  comprises a green laser source  2321  to generate a green laser L G  to pass through a first polarized spectroscope  2322  to generate a P polarized light P 5  reflected by a first reflecting panel  2323  to generate an S polarized light S 7 . The S polarized light S 7  is reflected by the first polarized spectroscope  2322  to generate a P polarized light P 4 . The P polarized light P 4  is transmitted from the first polarized light generator  232  to the second wave plate  235 , and then passes through the second wave plate  235  to transform into a P polarized light P 4  and then enter the X-prism  231 . 
     The second polarized light generator  233  comprises a blue laser source  2331  to generate a blue laser L B  to pass through a second polarized spectroscope  2332  to generate a P polarized light P 6  reflected by a second reflecting panel  2333  to generate an S polarized light S 8 . The S polarized light S 8  is reflected by the second polarized spectroscope  2332  to generate an S polarized light S 5 . The S polarized light S 5  is transmitted from the second polarized light generator  233  to the X-prism  231 , and enters the X-prism  231 . 
     The third polarized light generator  234  comprises a red laser source  2341  to generate a red laser L R  to pass through a third polarized spectroscope  2342  to generate a P polarized light P 7  reflected by a third reflecting panel  2343  to generate an S polarized light S 9 . The S polarized light S 9  is reflected by the third polarized spectroscope  2342  to generate an S polarized light S 6 . The S polarized light S 6  is transmitted from the third polarized light generator  234  to the X-prism  231 , and enters the X-prism  231 . 
     The X-prism  231  integrates the P polarized light P 4  generated by the first polarized light generator  232 , the S polarized light S 5  generated by the second polarized light generator  233  and the S polarized light S 6  generated by the third polarized light generator  234  into light to radiate. Light  24  comprises a P polarized light P 1 , an S polarized light S 1 , and an S polarized light S 2 . 
     After light  24  radiated by the laser engine  23  passes through the lens  21  for focus, light  24  passes through the first wave plate  62  to transform the P polarized light P 1  to an S polarized light S 3 , the S polarized light S 1  to a P polarized light P 2 , and the S polarized light S 2  to a P polarized light P 3 . Finally, an image is formed on the screen  20 . 
     During operation, the optical projection device  600  utilizes the first wave plate  62  to quickly move to change the angle between the light  24  and the axle of the first wave plate  62 , to change the direction of the electric field when light  24  moves. Thus, laser energy is equalized following variations of the interference position. Further, the interference speckle on the screen  20  is eliminated. Moreover, providing the laser source can reduce the quantity of the optical elements and the volume of the projector. Cost is decreased and the efficiency of production and assembly is increased. 
       FIG. 8  is a schematic view of an optical projection device of another embodiment of the invention. The optical projection device  800  comprises a lens  21 , a first wave plate  82  and a laser engine  23 . The laser engine  23  generates light  24  to pass through the lens  21  and the first wave plate  82 , forming into an image on a screen  20 . The first wave plate  82  rotates around an axle parallel to a projecting direction of light  24  by a motor (not shown) to equalize the laser energy and delete the interference speckle on the screen  20 . Referring to  FIG. 9 , the laser engine  23  comprises an X-prism  231 , a first polarized light generator  232 , a second polarized light generator  233 , a third polarized light generator  234  and a second wave plate  235 . The elements of the laser engine  23  are described as follows. 
     The first polarized light generator  232  comprises a green laser source  2321  to generate a green laser L G  to pass through a first polarized spectroscope  2322  to generate a P polarized light P 5  reflected by a first reflecting panel  2323  to generate an S polarized light S 7 . The S polarized light S 7  is reflected by the first polarized spectroscope  2322  to generate a P polarized light P 4 . The P polarized light P 4  is transmitted from the first polarized light generator  232  to the second wave plate  235 , and then passes through the second wave plate  235  to transform into a P polarized light P 4  and then enter the X-prism  231 . 
     The second polarized light generator  233  comprises a blue laser source  2331  to generate a blue laser L B  to pass through a second polarized spectroscope  2332  to generate a P polarized light P 6  reflected by a second reflecting panel  2333  to generate an S polarized light S 8 . The S polarized light S 8  is reflected by the second polarized spectroscope  2332  to generate an S polarized light S 5 . The S polarized light S 5  is transmitted from the second polarized light generator  233  to the X-prism  231 , and enters the X-prism  231 . 
     The third polarized light generator  234  comprises a red laser source  2341  to generate a red laser L R  to pass through a third polarized spectroscope  2342  to generate a P polarized light P 7  reflected by a third reflecting panel  2343  to generate an S polarized light S 9 . The S polarized light S 9  is reflected by the third polarized spectroscope  2342  to generate an S polarized light S 6 . The S polarized light S 6  is transmitted from the third polarized light generator  234  to the X-prism  231 , and enters the X-prism  231 . 
     The X-prism  231  integrates the P polarized light P 4  generated by the first polarized light generator  232 , the S polarized light S 5  generated by the second polarized light generator  233  and the S polarized light S 6  generated by the third polarized light generator  234  into light to radiate. Light  24  comprises a P polarized light P 1 , an S polarized light S 1 , and an S polarized light S 2 . 
     After light  24  radiated by the laser engine  23  passes through the lens  21  for focus, light  24  passes through the first wave plate  62  to transform the P polarized light P 1  to an S polarized light S 3 , the S polarized light S 1  to a P polarized light P 2 , and the S polarized light S 2  to a P polarized light P 3 . Finally, an image is formed on the screen  20 . 
     During operation, the optical projection device  800  utilizes the first wave plate  82  to quickly move to change the angle between the light  24  and the axle of the first wave plate  82 , to change the direction of the electric field when light  24  moves. Thus, laser energy is equalized following variations of the interference position. Further, the interference speckle on the screen  20  is eliminated. Moreover, providing the laser source can reduce the quantity of the optical elements and the volume of the projector. Cost is decreased and the efficiency of production and assembly is increased. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.