Abstract:
This invention provides compact photographic and projection modules and electronic systems having the photographic and projection modules, which not only can project image data but also can capture image with good image quality high zoom ratio. Additionally, the photographic and projection modules are reliable and able to be made with low cost.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of co-pending U.S. application Ser. No. 12/723,053 (Att. Docket AE8365P) filed Mar. 12, 2010 and entitled. “Photographic and Projection Device” which claims priority to Taiwan Patent Application No. 099101283 filed Jan. 18, 2010, and is also a continuation-in-part of U.S. application Ser. No. 13/347,470 (Att. Docket AE8652P) filed Jan. 10, 2012 and entitled. “ZOOM LENS” which claims priority to Taiwan Patent Application No. 100113555 filed Apr. 19, 2011, the entire contents all of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally relates to a photographic and projection module and an electronic system having the photographic and projection module. 
         [0004]    2. Description of Related Art 
         [0005]    Portable electronic products, such as multi-media mobile phones, mobile TV, digital cameras, digital video cameras, electronic game players, and mobile multi-media players, have become more and more popular with the common consumer in pervasive and even profound ways. The consumer has grown accustomed to watching multi-media data on portable electronic products. However, screen sizes of these portable electronic products tend to be so small as to make watching multi-media data for a long period of time difficult. To the extent a consumer may choose to view the multi-media data on a larger screen such as that of a conventional projector, this device, too, has many deficiencies. The volume of the conventional projector, for example, is too large to allow the device to be portable. Additionally, the light source of a conventional projector generates a large amount of heat. Moreover, the cooling fan of a conventional projector, in fulfilling its function to dissipate the heating problem, generates unacceptably high levels of noise. 
         [0006]    For the reason that there are some disadvantages of the prior art as mentioned, a need exists to propose a photographic and projection module so as to meet consumer needs. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, the present invention has been made in order to meet such a need described above, it being an object of the present invention to provide a photographic and projection module and electronic system so as to meet consumer needs. 
         [0008]    An embodiment of this invention provides a photographic and projection module, which comprises a zoom lens, an image sensor, a projection unit, and a first reflective member. The image sensor is used to catch images. The projection unit is used to project light beams. The first reflective member is disposed between the zoom lens and the image sensor or the projection unit. While the first reflective member is at a first position, an external image passes through the zoom lens then being caught by the image sensor. While the first reflective member is at a second position, the light beams are emitted by the projection unit, then refracted by the first reflective member, passing through the zoom lens, and then projected out of the photographic and projection module. 
         [0009]    Another embodiment of this invention provides an electronic system comprising a housing, a cover lens, and a photographic and projection module. The housing has an opening, and the cover lens covers the opening of the housing. The photographic and projection module comprises a fixed reflective member arranged at an optical axis and inside the housing; a zoom lens arranged following the fixed reflective member on the optical axis; a movable reflective member disposed following the zoom lens to change positions between a first position and a second position; an image sensor arranged at a first side of the movable reflective member; and a panel arranged at a second side of the movable reflective member; wherein when the movable reflective member is at the first position, first image beams pass through the cover lens, then being reflected by the fixed reflective member, zoomed by the zoom lens, and then focused on the image sensor, and when the movable reflective member is at the second position, the panel emitting the second image beams, which are then reflected by the movable reflective member, zoomed by the zoom lens, reflected by the fixed reflective member, and passed out of the cover lens and the opening. 
         [0010]    Another embodiment of this invention provides an electronic system having a housing and a photographic and projection module, the photographic and projection module having a zoom lens, an image sensor and a projection unit, and the photographic and projection module comprising: a fixed reflective member; and a movable reflective member used to switch an optical path; wherein while the movable reflective member is located at a photographic position, an external image is caught by the image sensor; and wherein while the movable reflective member is located at a projection position, an internal image are projected out of the photographic and projection module. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a photographic and projection module in accordance with an embodiment of the present invention. 
           [0012]      FIG. 2A  and  FIG. 2B  show different operation methods of the photographic and projection module. 
           [0013]      FIG. 3A  and  FIG. 3B  are two perspective views of an electronic system having a photographic and projection module in accordance with another embodiment of the present invention, in which  FIG. 3A  is image-capturing mode and  FIG. 3B  is image-projecting mode. 
           [0014]      FIG. 4  shows the theory of the prisms used in this invention. 
           [0015]      FIG. 5A  to  FIG. 5C  show a zoom lens ZL used in the photographic and projection modules and the electronic systems of this invention., wherein  FIG. 5A  and  FIG. 5B  respectively show the zoom lens in the telephoto end and the wide-angle end of the image-capturing operation, and  FIG. 5C  shows the zoom lens in an image-projecting operation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    A detailed description of the present invention will be discussed in connection with the following embodiments, which are not intended to limit the scope of the present invention and which can be adapted for other applications. While the drawings are illustrated in detail, it is to be appreciated that the quantity of the disclosed components may be greater or less than that disclosed except for instances expressly restricting the amount of the components. 
         [0017]      FIG. 1  provides a perspective view of a photographic and projection module  200  in accordance with an embodiment of the present invention. The photographic and projection module  200  includes an image sensor  210 , a zoom lens  220 , a movable reflective member  230 , and a projection unit  240 . 
         [0018]    The zoom lens  220  is disposed over the image sensor  210 , and the zoom lens  220  may comprise a fixed reflective member  260  and at least one lens group and each group comprises at least one lens. The zoom lens  220  is used for optical operations, such as focusing, zoom-in, zoom-out, and so on. The movable reflective member  230  has a reflective surface  231 , and may be disposed between the zoom lens  220  and the image sensor  210  or removed away from an optical axis of the photographic and projection module  200 . The projection unit  240  is located towards the reflective surface  231  of the movable reflective member  230 . 
         [0019]    In one embodiment, the projection unit  240  mainly comprises a display panel and at least one light source  250 . The reflective surface  231  of the movable reflective member  230  is capable of changing the path of light beams from the projection unit  240 , and the movable reflective member  230  is capable of changing position among a plurality of positions, such as a first position and a second position. For instance, when the movable reflective member  230  is located at the first position, a plurality of external light beams may pass through the zoom lens  220  and an external image can be formed on the image sensor  210 ; when the movable reflective member  230  is located at the second position, the light beams provided by the projection unit  240  may be projected to the outside via the movable reflective member  230  and the zoom lens  220 . 
         [0020]      FIG. 2A  and  FIG. 2B  show, respectively, two different operation methods of the photographic and projection module  200 . Referring to  FIG. 2A , one operation method comprises the movable reflective member  230  being located at the first position whereby the movable reflective member  230  will not interfere with the external light beams. Therefore, the external light beams can be passed through the zoom lens  220  and be formed the external image by the image sensor  210 . 
         [0021]    Moreover, with reference to  FIG. 2B , another operation method comprises the movable reflective member  230  being located at the second position whereby the external light beams cannot be caught by the image sensor  210 , and the light beams from the projection unit  240  can be projected to the outside of the photographic and projection module  200  via the movable reflective member  230  and the zoom lens  220 . 
         [0022]    In this embodiment, the movable reflective member  230  may be a movable reflective mirror or a movable prism, and the movable prism may be a reflective coating prism with a reflective surface or a total reflection prism with a total reflective surface. The movable reflective mirror and the reflective coating prism respectively comprise a reflective surface which is coated with an optical reflective film, such as dielectric film or metal film. Otherwise, the total reflective surface of the total reflection prism does not have any optical coating whose position is changed between the first position and the second position by rotation or linear movement, with the arrangement being provided by way of illustration rather than restriction such that the present invention should not be limited to this. Moreover, in this embodiment, the image sensor  210  may be a charge-coupled device (CCD) or a Complementary Metal-Oxide Silicon (CMOS) image sensor, but again the invention should not be limited to this. 
         [0023]    In the current embodiment, the projection unit  240  may comprise a Liquid Crystal Display (LCD) panel which is preferably a reflection-type LCD panel. The projection unit  240  may further comprise at least one light source  250 , wherein the light source  250  may preferably be a Light Emitting Diode (LED) light source for emitting light beams. Although specific details of the projection unit  240  have been illustrated and described in the embodiment mentioned above, the design of the projection unit  240  is not to be so limited. Based on different needs, the projection unit  240  can comprise other kinds of image display devices or other designs. 
         [0024]    According to this embodiment, the fixed reflective member  260  of the zoom lens  220  may be a fixed reflective mirror or a fixed prism, and the fixed prism may be a reflective coating prism with a reflective surface or a total reflection prism with a total reflective surface. The fixed reflective mirror and the reflective coating prism respectively comprise a reflective surface which is coated with an optical reflective film, such as dielectric film or metal film. Otherwise, the total reflective surface of the total reflection prism has no optical coating. The optical operations, such as focusing, zoom-in, and zoom-out, can be performed within the photographic and projection module  200  so as to prevent affecting the industry design of the photographic and projection module  200 . Hence, the photographic and projection module  200  can be compacted in an electronic system, such as a digital camera, a cell phone, a global positioning system (GPS), and a personal digital assistant (PDA), but is not limited to this. Based on different needs, the photographic and projection module  200  can comprise other industry designs or other structural designs. 
         [0025]      FIG. 3A  and  FIG. 3B  show an electronic system  300  having a photographic and projection module according to another embodiment of this invention, in which  FIG. 3A  shows the electronic system  300  for capturing the external image, and  FIG. 3B  shows the electronic system  300  for projecting the light beams provided by the projection unit  240 . For simplicity, components with same or similar reference numbers refer to same or similar components of the foregoing embodiments, and the detailed description, modifications, equivalents, and alternatives of which will be omitted. 
         [0026]    Referring to  FIG. 3A  and  FIG. 3B , in this embodiment, a fixed prism  310  is used as the fixed reflective member  260 , and a movable prism  330  is used as the movable reflective member  230  of the photographic and projection module  200 . The electronic system  300  comprises a housing  340  with an opening (not shown) and a photographic and projection module, which can be practiced within the housing  340 . The photographic and projection module preferably comprises a cover lens  320 , a zoom lens  220 , the movable prism  330 , an image sensor  210  and a projection unit  240 . The fixed prism  310  is arranged at an optical axis OA of the photographic and projection module. The zoom lens  220  comprises the fixed prism  310  which is on the optical axis OA. The movable prism  330  is disposed following the zoom lens  220  to change positions between a first position and a second position. The image sensor  210  is arranged at a first side of the movable prism  330 , and the projection unit  240  is arranged at a second side of the movable prism  330 . The cover lens  320  and other components of the photographic and projection module as well as their activities, including the zooming and focusing of the zoom lens  220 . 
         [0027]    The fixed prism  310  may be a reflective coating prism with a reflective surface or a total reflection prism with a total reflective surface for the light beams from the projection unit  240 . Specifically, the fixed prism  310  includes a first surface  311 , a second surface  312 , and a third surface  313 . Typically, at least one of the first surface  311  and the third surface  313  is coated with an anti-reflective film. Additionally, the second surface  312  of the reflective coating prism is coated with an optical reflective film, such as dielectric film or metal film. Otherwise, the second surface  312  of the total reflection prism does not have any optical reflective film. 
         [0028]    The movable prism  330  may be a reflective coating prism with a reflective surface or a total reflection prism with a total reflective surface for the light beams. The movable prism  330  includes a first surface  331 , a second surface  332 , and a third surface  333 . Typically, at least one of the first surface  331  and the third surface  333  are coated with an anti-reflective film, and the second surface  332  is coated with an optical reflective film, such as dielectric film or metal film; the second surface  332  of the total reflection prism with no optical reflective film. Similar to the embodiment of  FIGS. 2A and 2B , the movable prism  330  is able to change its position between a first position and a second position, as respectively shown in  FIG. 3A  and  FIG. 3B , by rotation or movement, and preferably by rotation. Modifications may be made to the above embodiment. 
         [0029]    Referring to  FIG. 3A , when the movable prism  330  is at the first position, the external image passes through the cover lens  320  and the zoom lens  220 , and then focuses the image on the image sensor  210 . Wherein the external image enters the fixed prism  310  via the first surface  311 , reflected via the second surface  312 , and transmitted out of the fixed prism  310  from the third surface  313 . 
         [0030]    Referring to  FIG. 3B , when the movable prism  330  is at the second position, the light source  250  emits light beams to render the display panel of the projection unit  240  reflecting the light beams in accordance with an internal image. The light beams of the internal image is projected into the movable prism  330  via the first surface  331 , reflected via the second surface  332 , and transmitted out of the movable prism  330  via the third surface  333 . The zoom lens  220  then focuses the light beams of the image, and the fixed prism  310  reflects the light beams via a reverse order mentioned before. The light beams are finally projected out of the electronic system  300  through the cover lens  320  and the opening. 
         [0031]      FIG. 4  illustrates a diagram of the movable prism  330  and the fixed prism  310  while the module  200  is projecting an image, according to another embodiment of this invention. Notice that this diagram is used to illustrate theory; the orientation of the prism  310 / 330  may be different from the real situation. Referring to  FIG. 4 , a first surface  331  and a third surface  333  of the movable prism  330  may be coated with an optical anti-reflection film; however, the second surface  332  is a bare surface. The fixed prism  310  and the movable prism  330  reflect the image beam by total internal reflection and to meet the total internal reflection, the prism  310 / 330  satisfies the following equation: 
         [0032]    n sin θc≧1, wherein n is the refractive index of the movable prism  330  or the fixed prism  310 , θc is a critical angle between the incident image beam and the normal vector of reflected surface, i.e., the second surface  332  or the second surface  312 . In current embodiment, the refractive index of the prisms  330 / 310  may range from 1.50 to 1.90, e.g., 1.53, and thus the critical angle θc=sin −1 (1/n)=sin −1 (1/1.53). Because the image beams from the display panel  240  is collimated, total internal reflection is easily achieved. Although the prisms  310 / 330  have triangular configuration in this example, in other embodiments, the movable prism  330  and/or the fixed prism  310  may have other configurations (e.g., elbow tube-shaped) and may have more than one bare reflective surface at its boundary and each surface reflects the image beam by total internal reflection. Namely, the prisms  310 / 330  may be total internal reflection (TIR) lens with triangular shape or other configurations. In addition, the mentioned fixed reflective member  260  may replace the fixed prism  310  in other embodiments. 
         [0033]    Additionally, a challenge is to provide good image quality with rigorous size requirement. According to a preferred embodiment of this invention,  FIG. 5A  to  FIG. 5C  show a zoom lens ZL used in the mentioned photographic and projection modules  200  or electronic system  300 , wherein  FIG. 5A  and  FIG. 5B  respectively show the zoom lens in the telephoto end and the wide-angle end of the image-capturing operation, and  FIG. 5C  shows the zoom lens in an image-projecting operation. For identification, image-forming surface I corresponds to the image sensor  210 , and lens group G 1 , G 2 , G 3 , and G 4  correspond to zoom lens  220  in which first lens L 11  corresponds to the cover lens  320 , prism P corresponds to the fixed prism  310 , and lens T corresponds to the movable prism  330 . 
         [0034]    As shown in  FIG. 5A  and  FIG. 5B , the zoom lens ZL primarily consists of, in order from an object side to an image-forming side, a first lens group G 1 , a second lens group G 2 , a third lens group G 3 , and a fourth lens group G 4  arranged along the optical axis OA, and an image-forming surface I is arranged at the image-forming side. The first lens group G 1  has positive refractive power, the second lens group G 2  has negative refractive power, the third lens group G 3  has positive refractive power, and the fourth lens group G 4  has positive refractive power. 
         [0035]    For needs of compact size, low cost, high zoom ratio, and good image quality, the zoom lens ZL satisfies the following conditions: 
         [0000]      4.0&lt; ft/fw&lt; 6.0; and   (1)
 
         [0000]      2.0&lt;| fG 1 /fG 2|&lt;4.0,   (2)
 
         [0000]    wherein fG 1  denotes the focal length of the first lens group G 1 , fG 2  denotes the focal length of the second lens group G 2 , fw denotes the focal length of the zoom lens ZL at the wide-angle end, and ft denotes the focal length of the zoom lens ZL at the telephoto end. 
         [0036]    As shown in  FIG. 5A  and  FIG. 5B , the zoom lens ZL may further comprise a stop S and a filter F. The (aperture) stop S may be arranged between the second lens group G 2  and the third lens group G 3 , for limiting the light flux of the image beam into the third lens group G 3 . The filter F may be arranged. between the fourth lens group G 4  and the image-forming surface I, for filtering invisible light off the image beam. The filter F may be an infrared light filter. In addition, a flat lens C, as a cover glass, may be arranged between the image-forming surface I and the filter F. 
         [0037]    In this embodiment, when the zoom ratio and the focal length of the zoom lens ZL are needed to be adjusted, the positions of the first lens group G 1  and the third lens group G 3  will be kept, and the second lens group G 2  and the fourth lens group G 4  are moved along the optical axis OA, so as to determine a zoom ratio. In detail, when zooming from the telephoto end to the wide-angle end, the second lens group G 2  and the fourth lens group G 4  are moved away from the third lens group G 3 . 
         [0038]    Referring to  FIGS. 5A to 5C  again, the zoom lens ZL comprises at least four aspheric lenses or free-form lenses. In detail, each of the four lens groups comprises an aspheric lens or a free-form lens made of plastic or glass. The plastic may comprise, but is not limited to, polycarbonate, cyclic olefin copolymer (e.g., APEL), polyester resins (e.g., OKP4 or OKP4HT), and the like. In addition, each free-form lens comprises at least one free-form freedom surface, and each aspheric lens comprises at least one aspheric surface satisfying the following equation (3): 
         [0000]    
       
         
           
             
               Z 
               = 
               
                 
                   
                     CY 
                     2 
                   
                   
                     1 
                     + 
                     
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               K 
                               + 
                               1 
                             
                             ) 
                           
                            
                           
                             C 
                             2 
                           
                            
                           
                             Y 
                             2 
                           
                         
                       
                     
                   
                 
                 + 
                 
                   
                     A 
                     4 
                   
                    
                   
                     Y 
                     4 
                   
                 
                 + 
                 
                   
                     A 
                     6 
                   
                    
                   
                     Y 
                     6 
                   
                 
                 + 
                 
                   
                     A 
                     8 
                   
                    
                   
                     Y 
                     8 
                   
                 
                 + 
                 
                   
                     A 
                     10 
                   
                    
                   
                     Y 
                     10 
                   
                 
                 + 
                 
                   
                     A 
                     12 
                   
                    
                   
                     Y 
                     12 
                   
                 
               
             
             , 
           
         
       
     
         [0000]    where Z is the coordinate in the optical axis OA direction in which direction light propagates is positive, A 4 , A 6 , A 8 , A 10 , and A 12  are aspheric coefficients, K is coefficient of quadratic surface, R is the radius of curvature, C is reciprocal of R(C=1/R), Y is the coordinate in a direction perpendicular to the optical axis in which the upward direction is positive, and coefficients of equation (3) of each aspheric lens are predetermined to determine the focal length and thus satisfy the above-mentioned conditions. 
         [0039]    In this preferred embodiment, the first lens group G 1  comprises, in order from the object side to the image-forming side, a first lens L 11 , a second lens L 12 , a third lens L 13 , in which the first lens L 11  is a negative convex-concave lens having a convex toward the object side, the second lens L 12  is a positive convex-concave lens having a convex toward the image-forming side, and the third lens L 13  is a positive biconvex lens. The second lens group G 2  comprises, in order from the object side to the image-forming side, a first lens L 21 , a second lens L 22 , a third lens L 23 , in which the first lens L 21  is a negative biconcave lens, the second lens L 22  is a negative convex-concave lens having a convex toward the image-forming side, and the third lens L 23  is a positive convex-concave lens having a convex toward the image-forming side. The third lens group G 3  comprises a first lens L 31 , which is a positive biconvex lens. The fourth lens group G 4  comprises, in order from the object side to the image-forming side, a first lens L 41 , a second lens L 42 , a third lens L 43 , and a fourth lens L 44 , in which the first lens L 41  is a positive biconvex lens, the second lens L 42  is a positive biconvex lens, the third lens L 43  is a negative biconcave lens, and the fourth lens L 44  is a negative convex-concave lens having a convex surface toward the object side. 
         [0040]    In addition, the zoom lens ZL may further comprise a reflector for deflecting the direction of the image beam. For example, the zoom lens ZL may deflect the direction of the image beam by 90°. In this preferred embodiment, the reflector is a prism P, arranged between the first lens L 11  and the second lens L 12  of the first lens group G 1 , for deflecting the optical path of the image beam and shortening the total length of the zoom lens ZL. 
         [0041]    Furthermore, in this preferred embodiment, the zoom lens ZL further satisfies the following condition: 
         [0000]      1.5&lt;PL/ fw&lt; 2.2,   (4)
 
         [0000]    wherein PL denotes the optical path length of the prism P for deflecting the image beam, i.e., the optical path of the image beam within the prism P. In another embodiment, condition (4) may be modified as 1.75&lt;PL/fw&lt;2.0. 
         [0042]    Notice that other embodiments of this invention may omit the reflector. In practical, the third lens L 13  of the first lens group G 1 , the first lens L 21  of the second group G 2 , the first lens L 31  of the third lens group G 3 , and the fourth lens L 44  of the fourth lens group G 4  are aspheric lenses with two aspheric surfaces or free-form lenses with two free-form freedom surfaces, and other lenses of the zoom lens are spherical glass lenses with two spherical surfaces. In this preferred embodiment, the third lens L 13  and the first lens L 31  are glass lenses, and the first lens L 21  and the fourth lens L 44  are plastic lenses. In addition, the second lens L 22  and the third lens L 23  of the second lens group G 2 , and the second lens L 42  and the third lens L 43  of the fourth lens group G 4 , may be glued to be a doublet lens. 
         [0043]    A preferred embodiment of the zoom lens and its aberration can be found in Table 1, Table 2, Table 3, and Table 4 and related drawings in the foregoing U.S. application Ser. No. 13/347,470 filed Jan. 10, 2012 and entitled “ZOOM LENS.” The zoom lens indeed reveals good image quality and also has advantages of compact size, high zoom ratio, and low cost. Although the zoom lens comprises four lens groups, other numbers of lens groups, e.g., one to three or five to six lens groups or more, may also be designed and adapted. 
         [0044]    Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.