Patent Publication Number: US-2011063498-A1

Title: Camera module for vehicles

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2009-0086356, filed on Sep. 14, 2009, entitled “Camera Module For Automobile”, which is hereby incorporated by reference in its entirety into this application. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a camera module for vehicles. 
     2. Description of the Related Art 
     Generally, mirrors are attached to predetermined portions of a vehicle to allow a desired direction or place including the front side, the right and left sides, the rear side and the interior of the vehicle to be viewed from a driver&#39;s seat when the vehicle is being driven. However, since the minors have the narrow field of view and cannot be seen when an obstacle is placed between the mirrors and a driver, the installing positions of the mirrors are restricted. Further, since the mirrors are installed at different positions, it is impossible to observe several directions with a single look and a driver must turn his or her head in respective directions, so that it is not easy to view them. While the driver watches one direction through any one of the minors, he or she may neglect to watch another direction, thus causing an unexpected accident. 
     A video monitoring system using a camera, in place of the mirrors of the vehicle, is known to those skilled in the art. That is, the camera is installed in place of the minors or the camera as well as the mirrors is installed, and a monitor in the form of a CCTV is installed near the driver&#39;s seat, so that the driver can watch the rear side by glancing at an image captured by the camera and displayed on the monitor. 
       FIG. 1  is a vertical perspective view illustrating the internal structure of a conventional camera module for vehicles. Hereinafter, the conventional camera module  10  for vehicles will be described with reference to the drawing. 
     As shown in  FIG. 1 , the conventional camera module  10  for vehicles includes a lens barrel  20 , an upper housing  30 , a circuit board  40 , and a lower housing  60 . 
     The lens barrel  20  functions to bring an image of a subject incident on a lens into the camera module  10 , and comprises a hollow cylindrical lens receptor having an internal to space of a predetermined size such that at least one lens is arranged along an optical axis. 
     Here, the lens barrel  20  has on its outer circumference an external threaded part and is fastened to the upper housing  30  in a threaded manner. After a focusing operation is performed using vertical movement generated by rotating the lens barrel  20 , the lens barrel  20  is attached to the upper housing  30  using additional adhesive means. 
     The upper housing  30  is an assembly receptor which holds the lens barrel  20 , and has the shape of a square box. An inner opening is formed through the central portion of the upper housing  30 , and the lens barrel  20  is accommodated in the inner opening. The upper housing  30  is adhered to the circuit board  40  using an adhesive. 
     The circuit board  40  functions to transmit an electric signal from the image sensor  50 , which is electrically connected to the upper surface of the circuit board  40 , to a mobile device such as a camera phone, a PDA or a notebook computer. The circuit board  40  is coupled to the upper housing  30 . 
     The lower housing  60  is fastened to the upper housing  30  to seal internal components including the circuit board  40  and the image sensor  50 , and is coupled to the upper housing  30  using an adhesive. Here, the lower housing  60  may be provided with a connector  70  which connects the camera module with an external device. 
     However, the conventional camera module  10  for vehicles is problematic in that there are many fastened parts, so that waterproof performance is low. That is, the conventional camera module  10  is problematic in that it inevitably has a first fastened part of the lens barrel  20  with the upper housing  30  and a second fastened part of the upper housing  30  with the lower housing  60 , so that waterproof performance is reduced at the fastened parts. Particularly, since the camera module  10  for vehicles is exposed to the outside when it is in use, the entire reliability of the camera module may be considerably reduced if the waterproof performance is lowered. Further, if the camera module  10  has many fastened parts, fastening operations must be performed several times, so that assemblability is low. 
     SUMMARY OF THE INVENTION 
     The present invention is intended to provide a camera module for vehicles, which reduces the number of fastened parts, thus improving waterproof performance and assemblability. 
     In an exemplary camera module for vehicles according to an embodiment of the present invention, an upper housing accommodates at least one lens which brings an image of a subject into focus. A circuit board has an image sensor mounted thereon, the image sensor converting the image received through the lens into an electric signal. A lower housing is fastened to the upper housing, thus sealing an internal space receiving the image sensor and the circuit board. 
     The upper housing may be integrated with a barrel part which has an inner opening for accommodating the lens. 
     Further, the upper housing and the lower housing may have a cylindrical structure, and may be fastened to each other in a threaded manner. 
     Parts of the upper housing and the lower housing which are fastened to each other in a threaded manner may be adhered using adhesive means. 
     Further, an external threaded part may be formed on an outer circumference of the upper housing, and an internal threaded part may be formed on an inner circumference of the lower housing to engage with the external threaded part. 
     An external threaded part may be formed on an outer circumference of the lower housing, and an internal threaded part may be formed on an inner circumference of the upper housing to engage with the external threaded part. 
     Further, the circuit board may be fastened to the lower housing. 
     The lower housing may be provided with an inner step for supporting the circuit board, and the circuit board may be coupled to the inner step using a screw. 
     Further, the upper housing may have an IR filter therein. 
     Furthermore, a connector for forming a connection with an external device may be fastened to the lower housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a vertical perspective view illustrating the internal structure of a conventional camera module for vehicles; and 
         FIG. 2  is a vertical perspective view illustrating the internal structure of a camera module for vehicles according to a preferred embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Various objects, advantages and features of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings. 
     The terms and words used in the present specification and claims should not be interpreted as being limited to typical meanings or dictionary definitions, but should be interpreted as having meanings and concepts relevant to the technical scope of the present invention based on the rule according to which an inventor can appropriately define the concept of the terms to describe most appropriately the best method he or she knows for carrying out the invention. 
     The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. Herein, the same reference numerals are used to throughout the different drawings to designate the same components. Further, when it is determined that the detailed description of the known art related to the present invention might obscure the gist of the present invention, the detailed description thereof will be omitted. 
     Hereinafter, the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 2  is a vertical perspective view illustrating the internal structure of a camera module for vehicles according to a preferred embodiment of the present invention. Hereinafter, a camera module  100  for vehicles according to this embodiment will be described with reference to the drawing. 
     As shown in  FIG. 2 , the camera module  100  for vehicles according to this embodiment includes an upper housing  110 , a circuit board  130 , and a lower housing  120 . 
     The upper housing  110  provides a space for accommodating a lens, and is fastened to the lower housing  120 , thus providing a sealing space for protecting internal components from the external environment. 
     Here, the upper housing  110  is integrated with a barrel part  112  which accommodates the lens therein. Such a structure reduces the number of fastened parts, and improves waterproof performance. The structure may be achieved by changing an injection molding process. The lens is accommodated in the barrel part  112  to be secured thereto. 
     The barrel part  112  is formed to have an inner opening of a predetermined size such that at least one lens is arranged along an optical axis, and is provided with a spacer (not shown) which is disposed between a plurality of lenses such that they are spaced apart from each other by a predetermined interval. Further, a cap is provided on the upper end of the barrel part  112  to hold the lenses arranged along the optical axis. Preferably, an incident hole of a predetermined size, corresponding to the center of the lens, is formed through the center of the front of the cap. 
     Further, the upper housing  110  has a cylindrical structure of a size which may wholly cover internal components including the circuit board  130  and an image sensor  140 , and an external threaded part  114  is formed on the outer circumference of the upper housing  110 . According to the conventional camera module, as shown in  FIG. 1 , the lens barrel  20  having on its outer circumference the external threaded part and the upper housing  30  on its inner circumference the internal threaded part are fastened to each other in a threaded manner, so that the lens barrel  20  is moved vertically, thus achieving the auto-focusing function. However, according to the present invention, the upper housing  110  is integrated with the barrel part  112  into a single structure, so that the auto-focusing function cannot be achieved by the vertical movement of the barrel part  112 . Thus, the external threaded part is formed on the outer circumference of the upper housing  110 , and the upper housing  110  is fastened to the lower housing  120 , so that, when the fastening operation is performed through the vertical movement of the upper housing  110 , the auto-focusing function is achieved. In this case, in order to achieve the vertical movement through the rotation of the upper housing  110 , the upper housing  110  has a cylindrical structure. Further, in order to achieve the auto-focusing function, the upper housing  110  has on its outer circumference the external threaded part  114 . Here, parts fastened in a threaded manner are adhered to each other using an adhesive means such as rubber or an adhesive after auto focusing. 
     Hereinbefore, an embodiment wherein the external threaded part is provided on the outer circumference of the upper housing  110  has been described. However, the upper housing  110  may have an internal threaded part. In this case, the lower housing  120  has on its outer circumference an external threaded part. Such a construction also falls within the scope of the present invention. 
     Further, an IR filter (not shown) is installed in the housing  120  to filter infrared to rays included in a light beam incident on the lens or to prevent impurities from falling onto the image sensor  140 . Preferably, the IR filter is placed on the same axis as at least one lens provided in the upper housing  110  and the image sensor  140 . 
     The circuit board  130  functions to transmit an electric signal, generated from the image sensor  140  which is electrically connected to the upper surface of the circuit board  130 , to a mobile device such as a camera phone, a PDA or a notebook computer. 
     Here, the image sensor  140  serves to convert an image into an electric signal. An image formation area is provided on the central portion of the upper surface of the image sensor  140 , and a sensor pad is provided on the edge of the image sensor  140  to be connected to the pad of the circuit board  130  via a wire. The image sensor  140  is attached to the central portion of the upper surface of the circuit board  130  using an adhesive. Meanwhile, the image sensor  140  may be mounted on the circuit board  130  through a flip-chip bonding method as well as a wire bonding method. 
     A plurality of chip devices is mounted on the circuit board  130  and digitizes an image signal output from the image sensor  140 . Especially, a passive component such as an MLCC for eliminating noise generated during the operation of a camera is mounted on the circuit board  130 . The chip devices are mounted on the edge of the circuit board  130 . 
     Meanwhile, the circuit board  130  is supported by an inner step of the lower housing  120  which will be described below in detail, and is fastened to the inner step using a screw  132 . According to the conventional camera module, the circuit board  130  is fastened to the upper housing  110 . However, according to the present invention, the auto focusing of the lens relative to the image sensor  140  is achieved through the coupling of the upper housing  110  with the lower housing  120  in a threaded manner. Thus, if the circuit board  130  is coupled to the upper housing  110 , it is impossible to adjust a distance between the lens and the image sensor  140 . Hence, it is preferable that the circuit board  130  be coupled to the lower housing  120 .  FIG. 2  illustrates an embodiment wherein the to circuit board  130  is coupled to the lower housing  120  using the screw. But, the circuit board may be adhered to the lower housing adhesive means. 
     The lower housing  120  is fastened to the upper housing  110 , thus providing an internal space which accommodates the internal components including the circuit board  130  and the image sensor  140 . 
     Here, the lower housing  120  has a cylindrical structure of a size which may wholly cover the internal components including the circuit board  130  and the image sensor  140 . The internal threaded part  122  is formed on the inner circumference of the lower housing  120 . 
     Preferably, the lower housing  120  has on its inner circumference the inner step for supporting the circuit board  130 . In the state where the circuit board  130  is supported by the inner step, the circuit board  130  is preferably coupled to the lower housing  120  using the screw  132 . 
     Meanwhile, a connector part  150  such as a cable for the connection of the cameral module with an external device is fastened to the lower portion of the lower housing  120 . 
     As described above, the present invention provides a camera module for vehicles, in which a lens barrel and an upper housing are integrated into each other unlike a conventional camera module, thus reducing the number of fastened parts. Thus, the waterproof performance and assemblability of the camera module for vehicles are improved. Further, an upper housing structure according to the present invention obviates the necessity of separately manufacturing the lens barrel, thus reducing the cost of materials. 
     Further, the present invention provides a camera module for vehicles, which is capable of performing an auto-focusing function by fastening an upper housing to a lower housing in a threaded manner, and of performing auto-focusing operation when the upper housing is fastened to the lower housing, thus simplifying work. 
     Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 
     Accordingly, such modifications, additions and substitutions should also be understood as falling within the scope of the present invention.