Patent Publication Number: US-2021181596-A1

Title: Camera front cover and camera therewith

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a camera, and more particularly to a front cover of a camera. 
     2. Description of the Prior Art 
     Common surveillance cameras are usually equipped with a front cover disposed in front of the lens of the surveillance camera. The surveillance camera uses an auxiliary light source, such as infrared light. The front cover of some cameras will cover the lens and the light source at the same time to provide structural protection. Generally, in order to prevent the light from the light source from being directly reflected by the front cover to enter the lens, the front cover usually adopts a design to separate light-penetrable portions corresponding to the lens and the light source. If the camera has a plurality of light sources arranged around the lens, the light-penetrable portions of the front cover will include an outer light-penetrable portion and a central light-penetrable portion in principle, corresponding to the light sources and the lens respectively. The outer light-penetrable portion and the central light-penetrable portion are usually connected by a structural member. In order to take into account the feasibility of manufacturing the front cover, the outer light-penetrable portion and the central light-penetrable portion are usually fixed to the structural member only by glue. This structural design is usually difficult to provide a sufficient structural strength of the front cover in the axial direction to be able to withstand the impact of foreign objects for a long time. Furthermore, after a foreign object hits the front cover, the waterproof capacity of the front cover will probably be reduced or even fail. 
     SUMMARY OF THE INVENTION 
     An objective of the invention is to provide a camera front cover, which uses two blocking structures disposed parallel to an axial direction of the camera front cover to enhance the axial structural strength of the camera front cover so that the waterproof capacity of the camera front cover can be maintained to a certain extent. 
     A camera front cover according to the invention has an axial direction and includes an outer frame, a supporting ring, an annular light-penetrable part, and a central light-penetrable part. The outer frame surrounds the axial direction and has a first inner connecting portion. The supporting ring surrounds the axial direction inside the outer frame. The supporting ring has an outer connecting portion and a second inner connecting portion opposite to the outer connecting portion. The annular light-penetrable part surrounds the axial direction and has a first outer fringe and an inner fringe. The annular light-penetrable part is connected to the first inner connecting portion through the first outer fringe. The annular light-penetrable part is connected to the outer connecting portion through the inner fringe. The central light-penetrable part has a second outer fringe. The central light-penetrable part is connected to the second inner connecting portion through the second outer fringe. Therein, one of the first inner connecting portion, the second inner connecting portion, and the outer connecting portion includes two blocking structures. The two blocking structures are disposed parallel to the axial direction to block the first outer fringe, the second outer fringe, or the inner fringe correspondingly. 
     Another objective of the invention is to provide a camera, which includes the above camera front cover. The camera front cover uses two blocking structures disposed parallel to the axial direction to enhance the axial structural strength of the camera front cover so that the waterproof capacity of the camera front cover can be maintained to a certain extent. 
     A camera according to the invention includes a device outer casing, a camera front cover, and an image-capturing device. The camera front cover is connected to the device outer casing to form an accommodating space. The image-capturing device is disposed in the accommodating space and includes a lens. The camera front cover has an axial direction and includes an outer frame, a supporting ring, an annular light-penetrable part, and a central light-penetrable part. The outer frame surrounds the axial direction and has a first inner connecting portion. The supporting ring surrounds the axial direction is disposed inside the outer frame. The supporting ring has an outer connecting portion and a second inner connecting portion opposite to the outer connecting portion. The annular light-penetrable part surrounds the axial direction and has a first outer fringe and an inner fringe. The annular light-penetrable part is connected to the first inner connecting portion through the first outer fringe. The annular light-penetrable part is connected to the outer connecting portion through the inner fringe. The central light-penetrable part has a second outer fringe. The central light-penetrable part is connected to the second inner connecting portion through the second outer fringe. The lens faces the central light-penetrable part and captures external images through the central light-penetrable part. Therein, one of the first inner connecting portion, the second inner connecting portion, and the outer connecting portion includes two blocking structures. The two blocking structures are disposed parallel to the axial direction to block the first outer fringe, the second outer fringe, or the inner fringe correspondingly. 
     Compared with the prior art, in the camera front cover according to the invention and the camera therewith, the two blocking structures are used to block the annular light-penetrable part or the central light-penetrable part correspondingly, for effectively structurally constrain the blocked portion of the annular light-penetrable part or the central light-penetrable part, so that the annular light-penetrable part or the central light-penetrable part can be effectively and firmly fixed in the axial direction. Thereby, the axial structural strength of the camera front cover can be improved and the waterproof capacity thereof can be maintained to a certain extent, which can effectively solve the problems in the prior art that the structural strength of the front cover is insufficient and it is difficult to maintain the waterproof capacity thereof. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a camera according to an embodiment. 
         FIG. 2  is a sectional view of the camera in  FIG. 1  along the line X-X. 
         FIG. 3  is an enlarged view of a camera front cover of the camera in  FIG. 2 . 
         FIG. 4  is an exploded view of some components of the camera front cover in  FIG. 2 . 
         FIG. 5  is a schematic diagram illustrating a camera front cover according to an embodiment. 
         FIG. 6  is a sectional view of the camera front cover in  FIG. 5  along the line Y-Y. 
         FIG. 7  is an exploded view of some components of the camera front cover in  FIG. 5 . 
         FIG. 8  is a schematic diagram illustrating a camera front cover according to an embodiment. 
         FIG. 9  is a sectional view of the camera front cover in  FIG. 8  along the line Z-Z. 
         FIG. 10  is an exploded view of some components of the camera front cover in  FIG. 8 . 
         FIG. 11  is a sectional view of a camera front cover according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1  to  FIG. 4 . A camera  1  according to an embodiment includes a device outer casing  12 , a camera front cover  14 , an image-capturing device  16 , a plurality of light sources  18 , and a control module  20 . The device outer casing  12  has an accommodating space  12   a  and is engaged with the camera front cover to accommodate other components. The control module  20  is electrically connected to the image-capturing device  16  and the plurality of light sources  18  (indicated by bold dashed lines) for controlling the operation of the image-capturing device  16  and the plurality of light sources  18 . The image-capturing device  16  includes a lens  162 . The lens  162  is toward the camera front cover  14 . 
     In the embodiment, the camera front cover  14  has an axial direction  14   a  (indicated by a chain line in figures) and includes an outer frame  142 , a supporting ring  144 , an annular light-penetrable part  146 , and a central light-penetrable part  148 . The outer frame  142  (e.g. formed by, but not limited to, a metal part) surrounds the axial direction  14   a  and has a first inner connecting portion  1422 . The supporting ring  144  surrounds the axial direction  14   a  inside the outer frame  142  and has an annular body  1440 , an outer connecting portion  1442  outside the annular body  1440 , and a second inner connecting portion  1444  inside the annular body  1440  opposite to the outer connecting portion  1442 . The annular light-penetrable part  146  surrounds the axial direction  14   a  and has a first outer fringe  1462  and an inner fringe  1464 . The annular light-penetrable part  146  is connected to the first inner connecting portion  1422  through the first outer fringe  1462 . The annular light-penetrable part  146  is connected to the outer connecting portion  1442  through the inner fringe  1464 . The central light-penetrable part  148  has a second outer fringe  1482 . The central light-penetrable part  148  is connected to the second inner connecting portion  1444  through the second outer fringe  1482 . The central light-penetrable part  148  faces the lens  162 . The lens  162  can captures external images through the central light-penetrable part  148 . The plurality of light sources  18  face the annular light-penetrable part  146 . Light (e.g. but not limited to Infrared light) emitted by the light source  18  can pass through the annular light-penetrable part  146  to provide the main light or auxiliary light for the lens  162  to capture images. 
     In the embodiment, the outer connecting portion  1442  is a single structure and includes two blocking structures  1442   a  and  1442   b  that are arranged parallel to the axial direction  14   a  to block an inner fringe  1464  of the annular light-penetrable part  146 . The blocking structures  1442   a  and  1442   b  protrude outward from the annular body  1440  radially (i.e. perpendicular to the axial direction  14   a ). The blocking structure  1442   a  is a blocker, and the blocking structure  1442   b  is a hook. The protruding height of the blocking structure  1442   b  from the annular body  1440  is much less than the protruding height of the blocking structure  1442   a  from the annular body  1440 , which helps the inner fringe  1464  to get stuck between the blocking structures  1442   a  and  1442   b  from the blocking structure  1442   b.  In practice, the profile of the blocking structure  1442   b  (including the protruding height from the annular body  1440 ) can be decided according to the amount of interference between the blocking structure  1442   b  and the inner fringe  1464  and the material characteristics. For example, the blocking structure  1442   b  can be designed to be elastic. Then, there may be a relatively large amount of interference between the blocking structure  1442   b  and the inner fringe  1464 , and the inner fringe  1464  can be smoothly inserted into the blocking structures  1442   a  and  1442   b.  Therein, the supporting ring  144  can be made of plastics. The profile of the blocking structure  1442   b  is not limited to the hook shape. For another example, the annular light-penetrable part  146  can have elasticity relative to the supporting ring  144 . Then, there may be a relatively large amount of interference between the blocking structure  1442   b  and the inner fringe  1464 , and the inner fringe  1464  can be smoothly inserted into the blocking structures  1442   a  and  1442   b.  Therein, the supporting ring  144  is a metal part, and the annular light-penetrable part  146  is made of plastics (e.g. but not limited to polycarbonate). Furthermore, the camera front cover  14  includes an adhesive  22   a  that joins the inner fringe  1464  of the annular light-penetrable part  146  with the blocking structure  1442   b  of the outer connecting portion  1442  in a fillet joint. The adhesive  22   a  covers the blocking structure  1442   b,  so that the adhesive  22   a  has the effect of reinforcing the blocking structure  1442   b  to block the inner fringe  1464 . The adhesive  22   a  itself also has a sealing effect. 
     In the embodiment, the second inner connecting portion  1444  is a single structure and as a whole is a blocker, so as to block the second outer fringe  1482  of the central light-penetrable part  148  in the axial direction  14   a.  The camera front cover  14  includes an adhesive  22   b  that joins the second outer fringe  1482  of the central light-penetrable part  148  with the annular body  1440  in a fillet joint relative to the second inner connecting portion  1444 . The adhesive  22   b  also has the effect of blocking the second outer fringe  1482 . The adhesive  22   b  itself also has a sealing effect. Furthermore, the supporting ring  144  includes a light-eliminating structure  1446 . The light-eliminating structure  1446  surrounds the central light-penetrable part  148  relative to the axial direction  14   a  to reduce or avoid light reflected toward the central light-penetrable part  148 , which prevents light from being reflected to the lens  162  and affecting the quality of the images captured outward by the lens  162 . In the embodiment, the light-eliminating structure  1446  is a stepped structure; however, it is not limited thereto in practice. 
     In the embodiment, the first inner connecting portion  1422  is a single structure and has an annular groove  1422   a  surrounding the axial direction  14   a.  Correspondingly, the first outer fringe  1462  of the annular light-penetrable part  146  has an annular protrusion  1462   a  that protrudes substantially parallel to the axial direction  14   a.  The annular protrusion  1462   a  is accommodated in the annular groove  1422   a.  An adhesive  22   c  fills the annular groove  1422   a.  The adhesive  22   c  has the effect of bonding the annular protrusion  1462   a  and the annular groove  1422   a  and also has a sealing effect. Furthermore, the first inner connecting portion  1422  has a joining surface  1422   b  that surrounds the axial direction  14   a  and is substantially parallel to the axial direction  14   a.  The adhesive  22   c  also fills the gap between the first outer fringe  1462  and the joining surface  1422   b  to connect the first outer fringe  1462  and the joining surface  1422   b.  In addition, in practice, the joining surface  1422   b  and/or a surface of first outer fringe  1462  opposite to the joining surface  1422   b  can thereon form threads or rough surfaces or other structures that can increase the contact area, and the adhesive  22   c  is also filled between them, which can enhance the bonding effect between the first inner connecting portion  1422  and the first outer fringe  1462 . 
     Please refer to  FIG. 5  to  FIG. 7 . A camera front cover  34  according to an embodiment is logically similar in structure to the camera front cover  14 . In practice, the camera front cover  34  can be appropriately modified in structure to replace the camera front cover  14  and be assembled to the camera  1 . For other descriptions about the camera front cover  34 , please refer to relevant descriptions of the camera front cover  14 , which will not described in addition. In the embodiment, the camera front cover  34  has an axial direction  34   a  (indicated by a chain line in the figures) and includes an outer frame  342 , a supporting ring  344 , an annular light-penetrable part  346 , and a central light-penetrable part  348 . The outer frame  342  surrounds the axial direction  34   a  and has a first inner connecting portion  3422 . The supporting ring  344  surrounds the axial direction  34   a  inside the outer frame  342  and has an annular body  3440 , an outer connecting portion  3442  outside the annular body  3440 , and a second inner connecting portion  3444  inside the annular body  3440  opposite to the outer connecting portion  3442 . The annular light-penetrable part  346  surrounds the axial direction  34   a  and has a first outer fringe  3462  and an inner fringe  3464 . The annular light-penetrable part  346  is connected to the first inner connecting portion  3422  through the first outer fringe  3462 . The annular light-penetrable part  346  is connected to the outer connecting portion  3442  through the inner fringe  3464 . The central light-penetrable part  348  has a second outer fringe  3482 . The central light-penetrable part  348  is connected to the second inner connecting portion  3444  through the second outer fringe  3482 . 
     In the embodiment, the outer connecting portion  3442  includes two blocking structures  3442   a  and  3442   b  that are disposed for blocking the inner fringe  3464  of the annular light-penetrable part  346 . The blocking structures  3442   a  and  3442   b  protrude outward from the annular body  3440  radially (i.e. perpendicular to the axial direction  34   a ). The blocking structure  3442   a  is a blocker, and the blocking structure  3442   b  is a hook. The structural constraint of the blocking structures  3442   a  and  3442   b  on the inner fringe  3464  is logically equivalent to the structural constraint of the blocking structures  1442   a  and  1442   b  on the inner fringe  1464 . For other descriptions about the blocking structures  3442   a  and  3442   b,  please refer to the relevant descriptions of the blocking structures  1442   a  and  1442   b,  which will not be described in addition. Furthermore, the camera front cover  34  has an adhesive  42   a  that joins the inner fringe  3464  of the annular light-penetrable part  346  with the blocking structure  3442   b  of the outer connecting portion  3442  in a fillet joint. The adhesive  42   a  covers the blocking structure  3442   b,  so that the adhesive  42   a  has the effect of reinforcing the blocking structure  3442   b  to block the inner fringe  3464 . The adhesive  42   a  itself also has a sealing effect. 
     In the embodiment, the second inner connecting portion  3444  includes two blocking structures  3444   a  and  3444   b  that are arranged parallel to the axial direction  34   a  to block the second outer fringe  3482  of the central light-penetrable part  348 . The structural constraint of the blocking structures  3444   a  and  3444   b  on the second outer fringe  3482  is logically equivalent to the structural constraint of the blocking structures  3442   a  and  3442   b  on the inner fringe  3464 . For other descriptions about the blocking structures  3444   a  and  3444   b,  please refer to the relevant descriptions of the blocking structures  3442   a  and  3442   b,  which will not be described in addition. Therein, in practice, the central light-penetrable part  348  can have elasticity relative to the supporting ring  344  and is conducive to the structural design of the blocking structures  3444   a  and  3444   b,  which will not be described in addition. Furthermore, the camera front cover  14  includes an adhesive  42   b  that joins the second outer fringe  3482  of the central light-penetrable part  348  with the blocking structure  3444   b  in a fillet joint. The adhesive  42   b  covers the blocking structure  3444   b,  so that the adhesive  42   b  has the effect of reinforcing the blocking structure  3444   b  to block the second outer fringe  3482 . The adhesive  42   b  itself also has a sealing effect. 
     In the embodiment, the first inner connecting portion  3422  has three joining surfaces  3422   a,    3422   b  and  3422   c  that surround the axial direction  34   a.  The joining surface  3422   a  is substantially parallel to the axial direction  34   a.  The joining surface  3422   b  is substantially perpendicular to the axial direction  34   a.  The joining surface  3422   c  is a tapered surface (of which the normal direction is toward a side of the annular light-penetrable part  346  and forms an acute angle (not indicated in the figures) relative to the axial direction  34   a ). An adhesive  42   c  fills the gaps between the joining surfaces  3422   a,    3422   b  and  3422   c  and the first outer fringe  3462  to connect the first outer fringe  3462  and the first inner connecting portion  3422 . Furthermore, the adhesive  42   c  also protrudes out from the junction surface of the first outer fringe  3462  and the first inner connecting portion  3422 ; that is, the protruding portion of the adhesive  42   c  is equivalent to joining the first outer fringe  3462  and the outer frame  342  in a fillet joint. In practice, for an example, but not limited thereto, after the first outer fringe  3462  is placed on the first inner connecting portion  3422 , the corner formed by the first outer fringe  3462  and the first inner connecting portion  3422  can be filled with the adhesive  42   c.  Then the adhesive  42   c  can flow into between the first outer fringe  3462  and the joining surface  3422   c,  between the first outer fringe  3462  and the joining surface  3422   b,  and between the first outer fringe  3462  and the joining surface  3422   a  in sequence by the capillary action. 
     Furthermore, in the embodiment, the first inner connecting portion  3422  includes a hook  3422   d  (at a distal end of the outer frame  342 ) that can hook the first outer fringe  3462 . From another aspect, the portion of the first inner connecting portion  3422  corresponding to the hook  3422   d  can be taken as a blocking portion  3422   e.  The blocking portion  3422   e  and the hook  3422   d  blocks two opposite sides of the first outer fringe  3462  respectively. Thereby, the hook  3422   d  and the blocking portion  3422   e  also perform the aforementioned holding and blocking functions of the blocking structures  3442   a  and  3442   b.  The hook  3422   d  and the blocking portion  3422   e  can be taken as two blocking structures on the first inner connecting portion  3422 . In addition, in the embodiment, the amount of structural interference between the hook  3422   d  and the first outer fringe  3462  is relatively small, and the annular light-penetrable part  146  is made of plastics, so that the outer frame  342  still can be made of metal. 
     Please refer to  FIG. 8  to  FIG. 10 . A camera front cover  54  according to an embodiment is structurally similar to the camera front cover  14 . In practice, the camera front cover  54  can be appropriately modified in structure to replace the camera front cover  14  and be assembled to the camera  1 . For other descriptions about the camera front cover  54 , please refer to relevant descriptions of the camera front cover  14 , which will not described in addition. In the embodiment, the camera front cover  54  has an axial direction  54   a  (indicated by chain line in the figures) and includes an outer frame  542 , a supporting ring  544 , an annular light-penetrable part  546 , and a central light-penetrable part  548 . The outer frame  542  surrounds the axial direction  54   a  and has a first inner connecting portion  5422 . The supporting ring  544  surrounds the axial direction  54   a  inside the outer frame  542  and has an annular body  5440 , an outer connecting portion  5442  outside the annular body  5440 , and a second inner connecting portion  5444  inside the annular body  5440  opposite to the outer connecting portion  5442 . The annular light-penetrable part  546  surrounds the axial direction  54   a  and has a first outer fringe  5462  and an inner fringe  5464 . The annular light-penetrable part  546  is connected to the first inner connecting portion  5422  through the first outer fringe  5462 . The annular light-penetrable part  546  is connected to the outer connecting portion  5442  through the inner fringe  5464 . The central light-penetrable part  548  has a second outer fringe  5482 . The central light-penetrable part  548  is connected to the second inner connecting portion  5444  through the second outer fringe  5482 . 
     In the embodiment, the outer connecting portion  5442  includes two blocking structures  5442   a  and  5442   b  that are arranged parallel to the axial direction  54   a  to block the inner fringe  5464  of the annular light-penetrable part  546 . The blocking structures  5442   a  and  5442   b  protrude outward from the annular body  5440  radially (i.e. perpendicular to the axial direction  54   a ). The blocking structure  5442   a  is a blocker; the blocking structure  5442   b  is a hook. The structural constraint of the blocking structures  5442   a  and  5442   b  on the inner fringe  5464  is logically equivalent to the structural constraint of the blocking structures  1442   a  and  1442   b  on the inner fringe  1464 . For other descriptions about the blocking structures  5442   a  and  5442   b,  please refer to the relevant descriptions of the blocking structures  1442   a  and  1442   b,  which will not be described in addition. Furthermore, the camera front cover  54  has an adhesive  62   a  that joins the inner fringe  5464  of the annular light-penetrable part  546  with the blocking structure  5442   b  of the outer connecting portion  5442  in a fillet joint. The adhesive  62   a  covers the blocking structure  5442   b,  so that the adhesive  62   a  has the effect of reinforcing the blocking structure  5442   b  to block the inner fringe  5464 . The adhesive  62   a  itself also has a sealing effect. 
     In the embodiment, the second inner connecting portion  5444  includes two blocking structures  5444   a  and  5444   b  that are arranged parallel to the axial direction  54   a  to block the second outer fringe  5482  of the central light-penetrable part  548 . The structural constraint of the blocking structures  5444   a  and  5444   b  on the second outer fringe  5482  is logically equivalent to the structural constraint of the blocking structures  5442   a  and  5442   b  on the inner fringe  5464 . For other descriptions about the blocking structures  5444   a  and  5444   b,  please refer to the relevant descriptions of the blocking structures  5442   a  and  5442   b,  which will not be described in addition. Furthermore, the camera front cover  54  includes an adhesive  62   b  that joins the second outer fringe  5482  of the central light-penetrable part  548  with the blocking structure  5444   a  in a fillet joint. The adhesive  62   b  itself also has a sealing effect. In practice, an adhesive can also be filled at the blocking structure  5444   b,  which can simultaneously enhance the effect of the blocking structure  5442   b  blocking the second outer fringe  5482  and provide a sealing effect. 
     In the embodiment, the first inner connecting portion  5422  has two joining surfaces  5422   a  and  5422   b  that surround the axial direction  54   a.  The joining surface  5422   a  is substantially parallel to the axial direction  54   a.  The joining surface  5422   b  is substantially perpendicular to the axial direction  54   a.  An adhesive  62   c  fills the gap between the joining surfaces  5422   a  and  5422   b  and the first outer fringe  5462  to connect the first outer fringe  5462  and the first inner connecting portion  5422  (or the joining surfaces  5422   a  and  5422   b  thereof). Furthermore, the joining surface  5422   b  has an offset structure  5422   c.  The adhesive  62   c  also fills the offset structure  5422   c.  The offset structure  5422   c  enhances the effect of the adhesive  62   c  bonding the first outer fringe  5462  with the first inner connecting portion  5422  by accommodating the adhesive  62   c.  Furthermore, in the embodiment, the first outer fringe  5462  has an annular protrusion  5462   a.  The annular protrusion  5462   a  protrudes substantially parallel to the axial direction  54   a  inside the outer frame  542  and is adjacent to the first inner connecting portion  5422 . The adhesive  62   c  also fills the gap between the annular protrusion  5462   a  and the first inner connecting portion  5422 . The annular protrusion  5462   a  not only increases the structural constraints between the annular light-penetrable part  546  and the outer frame  542 , but also increases the area where the first outer fringe  5462  and the first inner connecting portion  5422  are joined through the adhesive  62   c,  which enhances the bonding effect. Furthermore, in another embodiment, a thread-like structure can be disposed on the first inner connecting portion  5422  and/or the first outer fringe  5462  where the both are connected. The bonding area of the adhesive  62 C can be increased by the thread-like structure for enhancing the bonding effect. 
     Furthermore, in the embodiment, the first inner connecting portion  5422  includes a hook  5422   d  (at an end of the outer frame  542 ) capable of hooking the first outer fringe  5462 . From another aspect, the portion of the first inner connecting portion  5422  opposite to the hook  5422   d  can be taken as a blocking portion  5422   e.  The blocking portion  5422   e  and the hook  5422   d  blocks two opposite sides of the first outer fringe  5462  respectively. Thereby, the hook  5422   d  and the blocking portion  5422   e  also can perform the holding and blocking functions of the aforementioned blocking structures  5442   a  and  5442   b,  so the hook  5422   d  and the blocking portion  5422   e  can be taken as two blocking structures disposed on the first inner connecting portion  5422 . In addition, in the embodiment, the amount of structural interference between the hook  5422   d  and first outer fringe  5462  is relatively small, or the annular light-penetrable part  546  is made of plastics, so that the outer frame  542  still can be made of metal. 
     In the above embodiments, the annular light-penetrable parts  146 ,  346  and  546  and the outer frames  142 ,  342  and  542  are joined by adhesives and holding structures; however, in practice, they can be joined by other structures. Please refer to  FIG. 11 . A camera front cover  55  according to an embodiment is structurally similar to the camera front cover  54  and uses the reference numbers of the camera front cover  54 . For other descriptions about the camera front cover  55 , please refer to relevant descriptions of the camera front cover  54 , which will not described in addition. A main difference between the camera front cover  55  and the camera front cover  54  is that in the camera front cover  55 , the first inner connecting portion  5422  of the outer frame  542  has a thread  5422   f  (e.g. an internal thread), the first outer fringe  5462  of the annular light-penetrable part  546  has a mating thread  5462   b  (e.g. an external thread), and the first outer fringe  5462  and the first inner connecting portion  5422  are engaged with each other through the thread  5422   f  and the thread  5462   b.  In addition, in practice, if the material of the annular light-penetrable part  546  is relatively soft to that of the outer frame  542 , it is practicable not to form the thread  5462   b  on the first outer fringe  5462  in advance. By directly screwing the first outer fringe  5462  onto the thread  5422   f,  the thread  5422   f  can directly mark the thread  5462   b  on the first outer fringe  5462 . 
     In addition, in the camera front covers  14  and  34 , a fastening ring can be used to engaged with the outer frames  142  and  342  (e.g. through threaded structures) for clamping the annular light-penetrable parts  146  and  346 . Similarly, the camera front cover  55  can be modified appropriately to remove the thread  5422   f  and the thread  5462   b  and use a fastening ring to engage with the outer frame  542  through threaded structures for clamping the annular light-penetrable part  546 . 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.