Abstract:
The present invention relates to an optical contact module. The optical contact module comprises an optical device receiving member ( 20 ) including an optical device receiving portion ( 21 ) formed with an optical device receiving space for receiving an optical device therein, an optical fiber receiving portion ( 23 ) formed with an optical fiber receiving space for receiving an optical fiber therein, a contact hole ( 22 ) for communicating the optical device receiving portion ( 21 ) with the optical fiber receiving portion ( 23 ), a slit ( 27 ) formed on the optical fiber receiving portion ( 23 ) and a projection portion extended from the distal end of the optical device receiving portion; an optical fiber fixing cap ( 10 ) including a receiving portion ( 13 ), and a through-hole ( 12 ); and a fastening means for detachably fastening the optical fiber fixing cap ( 10 ) to the optical device receiving member ( 20 ).

Description:
This application is a 371 of PCT/KR03/02429, filed Nov. 12, 2003. 
   FIELD OF THE INVENTION 
   The present invention relates to an optical contact module, and more particularly, to an optical contact module capable of easily connecting a single optical fiber for transmitting an optical signal with an optical transmission terminal or an optical reception terminal in such a manner that the optical signal does not leak. 
   BACKGROUND 
   Generally, an optical fiber comprises a core through which an optical signal is transmitted, a clad for enclosing the core, and a sheath layer for protecting the core and the clad. 
   In a case where a single optical fiber is used for a security system, the optical fiber is installed to measure dynamic or static changes in an optical signal transmitted through the optical fiber, or to measure physical fluctuation in the optical fiber using back scattering of the optical signal. 
   A technique regarding a security system using an optical fiber is disclosed in PCT Application No. PCT/KR02/0164 entitled “Security System Using Optical Fiber and Method of Controlling the Same” and filed on Aug. 30, 2002 by the present applicant. Particularly, when the optical fiber is connected to an optical transmitter module and an optical receiver module in the invention of this application, an optical contact means capable of easily connecting optical fibers that have been cut to have appropriate lengths in place is required. 
   Further, the optical contact means for use in such a security system is required to have the function of avoiding optical loss and shielding noises from the outside by completely sealing a contact portion. 
   Moreover, the optical contact means for use in such a security system is required to have the function of protecting the security system in such a manner that when external force exceeding a predetermined value is applied to the optical fiber, the optical fiber is easily separated from the security system to prevent the security system from being damaged. 
   Further, the optical contact means for use in such a security system is required to have the function of allowing a damaged or antiquated optical fiber to be easily replaced and reinstalled from the outside. 
   However, since the conventional optical contact means has a structure for fixing the optical fiber by compressing a sheath of the optical fiber with a metal piece, inexact dimensions of the metal piece may damage the core or clad of the optical fiber. Therefore, there is a problem that since the metal piece should be precisely machined, manufacturing costs thereof are increased. 
   Furthermore, there is a problem that if the optical contact means is molded with synthetic resin or the like to be completely sealed, it is impossible to properly adjust the length of the optical fiber and reinstall the optical fiber according to installation conditions. 
   SUMMARY 
   The present invention is conceived to solve the problems of the conventional optical contact means. Accordingly, an object of the present invention is to provide an optical fiber contact means having the functions required upon connection of optical fibers in a security system employing optical fibers that has been proposed by the present applicant. 
   Specifically, an object of the present invention is to provide an optical contact module capable of easily connecting optical fibers cut to have proper lengths in place, avoiding optical loss and shielding noises from the outside by completely sealing a contact portion, preventing a security system from being damaged by causing an optical fiber to be easily separated from the security system if external force exceeding a predetermined value is applied to the optical fiber, allowing a damaged or antiquated optical fiber to be easily replaced from the outside, and fixedly supporting the optical fiber with appropriate elastic force without damage to a core or clad of the optical fiber. 
   The optical contact module of the present invention connects a single optical fiber for transmitting an optical signal to an optical device such as a light emitting device or a light receiving device. The optical contact module comprises an optical device receiving member including an optical device receiving portion formed with an optical device receiving space for receiving the optical device therein from one end of the optical device receiving member, an optical fiber receiving portion formed with an optical fiber receiving space for receiving an optical fiber therein from the other end thereof, a contact hole having a predetermined diameter to communicate the optical device receiving portion with the optical fiber receiving portion, and a slit formed in the optical fiber receiving portion by removing a portion of an outer periphery of the optical fiber receiving portion by a predetermined length from the other end; an optical fiber fixing cap including a receiving portion which has a taper formed lengthwise such that the inner diameter of the receiving portion can be decreased to radially press the optical fiber receiving portion formed with the slit when the optical fiber receiving portion of the optical device receiving member is to be received therein from one end of the optical fiber fixing cap, and a through-hole at the other end thereof so that the optical fiber can be inserted into the receiving portion; and a fastening means formed on the outer periphery of the optical fiber receiving portion of the optical device receiving member and on an inner periphery of the receiving portion of the optical fiber fixing cap to detachably fasten the optical fiber fixing cap to the optical device receiving member. 
   According to the present invention, when the optical fiber fixing cap is coupled to the optical device receiving member, the slit formed in the optical fiber receiving portion is compressed by the taper of the optical fiber fixing cap, thereby fixing the optical fiber with elastic force. 
   Preferably, the optical contact module further comprises a projection portion extending lengthwise from a distal end of the optical device receiving portion of the optical device receiving member. The optical fiber receiving portion of the optical device receiving member is formed with a taper such that the outer diameter of the optical fiber receiving portion is increased from a distal end thereof, and a plurality of slits are formed circumferentially at a predetermined interval in the optical fiber receiving portion. 
   According to the present invention, the projection portion is inserted into a groove of an optical transmitter module or an optical receiver module to fix the optical device receiving member so that the optical device receiving member does not rotate when the optical fiber fixing cap is coupled to the optical device receiving member, thereby ensuring easy coupling of them. 
   Preferably, the optical contact module further comprises an optical fiber supporting member which is made of an elastic material, has a through-hole for receiving the optical fiber therein and is inserted into the optical fiber receiving portion of the optical device receiving member. 
   Preferably, a step is formed due to the outer diameter of the optical device receiving portion of the optical device receiving member larger than that of the optical fiber receiving portion thereof, and the optical contact module further comprises an O-ring fitted around the outer periphery of the optical fiber receiving portion and interposed between the step and the optical fiber fixing cap. 
   According to the present invention, the optical fiber supporting member supports the optical fiber without damage to a sheath of the optical, and alleviates differences in dimensions therebetween, and the O-ring prevents intrusion of raindrops from the outside. 
   Preferably, the fastening means comprises male threads formed on the outer periphery of the optical fiber receiving portion of the optical device receiving member and female threads formed on the inner periphery of the receiving portion of the optical fiber fixing cap. 
   Preferably, a pair of projection portions are formed on the optical device receiving member. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a perspective view of an optical contact module according to an embodiment of the present invention. 
       FIG. 2  is an exploded perspective view of the optical contact module of  FIG. 1 . 
       FIG. 3   a  is a sectional view taken along line A—A in  FIG. 1 . 
       FIG. 3   b  is a sectional view taken along line A—A in another example of the optical contact module of  FIG. 1 . 
       FIG. 4  is an exploded perspective view of an optical contact module according to another embodiment of the present invention. 
       FIG. 5   a  is a sectional view taken along line B—B in  FIG. 4 . 
       FIG. 5   b  is a sectional view taken along line B—B in another example of the optical contact module of  FIG. 4 . 
       FIG. 6  is a schematic view showing the constitution of a security system employing an optical contact module according to an embodiment of the present invention. 
       FIG. 7  is a view showing a state where the security system employing the optical contact module according to the embodiment of the present invention is used. 
       FIG. 8   a  is an exploded perspective view of portion C in the security system of  FIG. 7 . 
       FIG. 8   b  is an exploded perspective view of portion C in another example of the security system of  FIG. 7 . 
       FIG. 9   a  is a sectional view of portion C in the security system of  FIG. 7 . 
       FIG. 9   b  is a sectional view of portion C in the other example of the security system of  FIG. 7 . 
   

   EXPLANATION OF REFERENCE NUMERALS FOR DESIGNATING MAIN COMPONENTS IN THE DRAWINGS 
     10 : Optical fiber fixing cap  12 : Through-hole 
     13 : Receiving portion  15 ,  25 : Taper 
     16 : Female thread  17 : Coupling groove 
     20 : Optical device receiving member  21 : Optical device receiving portion 
     22 : Contact hole  23 : Optical fiber receiving portion 
     24 : Projection portion  26 : Male thread 
     27 : Slit  28 : Coupling ridge 
     100 : Optical contact module  110 : Optical fiber supporting member 
     120 : O-ring  220 : Optical fiber 
     300 : Control unit  400 : Optical transmitter module 
     500 : Optical receiver module 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     FIG. 1  is a perspective view of an optical contact module according to an embodiment of the present invention,  FIG. 2  is an exploded perspective view of the optical contact module of  FIG. 1 ,  FIG. 3   a  is a sectional view taken along line A—A in  FIG. 1 , and  FIG. 3   b  is a sectional view taken along line A—A in another example of the optical contact module of  FIG. 1 . 
   As shown in  FIG. 1 , the optical contact module according to the embodiment of the present invention comprises an optical device receiving member  20  for accommodating a light emitting device or a light receiving device, and an optical fiber fixing cap  10  that is fastened to the optical device receiving member  20  and fixes an optical fiber. 
   As shown in  FIGS. 2 and 3 , the optical device receiving member  20  has an optical device receiving portion  21  extending from one end into the optical device receiving member to receive the light emitting device or the light receiving device, and further has an optical fiber receiving portion  23  extending by a predetermined length from the other end into the optical device receiving member to receive an optical fiber. A single optical fiber, preferably, a plastic optical fiber is used as the optical fiber. Further, an contact hole  22  with a predetermined diameter is formed to communicate the optical device receiving portion  21  with the optical fiber receiving portion  23 , so that when the optical device received in the optical device receiving portion  21  is a light emitting device, light or an optical signal output from the light emitting device is transmitted to the optical fiber received in the optical fiber receiving portion  23 , while when the optical device received in the optical device receiving portion  21  is a light receiving device, an optical signal from the optical fiber received in the optical fiber receiving portion  23  is transmitted to the light receiving device received in the optical device receiving portion  21 . Of course, a portion of an end of the optical fiber may be inserted into the contact hole upon actual installation of the optical fiber. Further, a projection portion  24  extending lengthwise from the end of the optical device receiving portion  21  is additionally provided so that the optical contact module  100  can be inserted into a substrate of an optical transceiver module to be described later. Moreover, the optical fiber receiving portion  23  is formed with a taper  25  such that the outer diameter of the optical fiber receiving portion  23  can increase over a predetermined length from a distal end thereof. A plurality of slits  27  are formed in the optical fiber receiving portion  23  by removing some portions of an outer periphery of the optical fiber receiving portion  23  from the distal end thereof to have a length larger than that of the taper  25 . Male threads  26  are formed as a fastening means on the outer periphery to be screwed into the optical fiber fixing cap  10 . Meanwhile, one projection portion  24  can be provided as shown in  FIG. 3   a,  or a pair of projection portions  24  may be provided to be caught in both sides of the substrate of the optical transceiver module as shown in  FIG. 3   b.    
   As shown in  FIGS. 2 and 3 , the optical fiber fixing cap  10  has a receiving portion  13  extending from one end into the optical fiber fixing cap to receive the optical fiber receiving portion  23  of the optical device receiving member  20 , and further has a throughhole  12  at the other end thereof so that the optical fiber can pass through the receiving portion  13 . A taper  15  is formed lengthwise in the receiving portion  13  such that the inner diameter of the receiving portion can be decreased. Thus, when the taper  15  comes into contact with the taper  25  formed in the optical fiber receiving portion  23  of the optical device receiving member  20 , the optical fiber receiving portion  23  with the slots  27  is radially pressed. Further, female threads  16  are formed as a fastening means on an inner surface of the receiving portion  13  to be engaged with the male threads  26  formed in the optical fiber receiving portion  23 . 
   The optical contact module may further comprise an optical fiber supporting member to be received in the optical fiber receiving portion  23  to fix the optical fiber. The optical fiber supporting member is made of rubber or the like that is an elastic material and has a through-hole for receiving the optical fiber therein. 
   Moreover, a step is formed due the outer diameter of the optical device receiving portion  21  of the optical device receiving member  20  larger than that of the optical fiber receiving portion  23 , and the optical contact module may further comprise an O-ring fitted around the outer periphery of the optical fiber receiving portion  23  to be placed between the step and the optical fiber fixing cap  10 . 
     FIG. 4  is an exploded perspective view of an optical contact module according to another embodiment of the present invention,  FIG. 5   a  is a sectional view taken along line B—B in  FIG. 4 , and  FIG. 5   b  is a sectional view taken along line B—B in another example of the optical contact module of  FIG. 4 . 
   As shown in  FIG. 4 , the optical contact module  100  according to the other embodiment of the present invention comprises an optical device receiving member  20  for accommodating a light emitting device or a light receiving device, and an optical fiber fixing cap  10  that is fastened to the optical device receiving member  20  and fixes an optical fiber. As shown in  FIG. 5 , the optical device receiving member  20  is formed with a coupling ridge  28  having a predetermined height on the outer periphery of the optical fiber receiving portion  23 , and a coupling groove  17  having a predetermined depth is formed in an inner surface of the optical fiber fixing cap  10  to be coupled to the coupling ridge  28 . Therefore, although the optical contact module  100  according to the other embodiment of the present invention does not have the male threads  26  and the female threads  16  of the optical contact module of the previous embodiment, the coupling groove  17  of the optical fiber fixing cap  10  and the coupling ridge  28  of the optical device receiving member  20  are coupled to each other as a coupling means. The function of fixing and connecting the optical fiber is the same as the previous embodiment. Meanwhile, one projection portion  24  can be provided to be inserted into the substrate of the optical transceiver as shown in  FIG. 5   a,  or a pair of projection portions may be provided to be caught in both sides of the substrate of the optical transceiver module as shown in  FIG. 5   b.    
   The operation and effects of an optical contact module according to an embodiment of the present invention will be described hereinafter in connection with a security system employing an optical fiber as an optical fiber sensor. 
     FIG. 6  is a schematic view showing the constitution of a security system employing an optical contact module according to an embodiment of the present invention,  FIG. 7  is a view showing a state where the security system employing the optical contact module according to the embodiment of the present invention is used,  FIG. 8   a  is an exploded perspective view of portion C in the security system of  FIG. 7 ,  FIG. 8   b  is an exploded perspective view of portion C in another example of the security system of  FIG. 7 ,  FIG. 9   a  is a sectional view of portion C in the security system of  FIG. 7 , and  FIG. 9   b  is a sectional view of portion C in the other example of the security system of  FIG. 7 . 
   As shown in  FIG. 6 , the security system employing the optical contact module according to the embodiment of the present invention comprises an optical transmitter module  400  for outputting a predetermined optical signal, an optical receiver module  500  for receiving the optical signal output from the optical transmitter module  400  and converting the optical signal into a predetermined electric signal, an optical fiber  200  for transmitting the optical signal, the optical contact module  100  for connecting both ends of the optical fiber  200  to the optical transmitter module  400  and the optical receiver module  500 , respectively, and a control unit  300  for controlling the optical transmitter module  400  and the optical receiver module  500 . 
   As shown in  FIG. 7 , the optical transmitter module  400 , the optical contact module  100 , the optical fiber  200 , the optical contact module  100  and the optical receiver module  500  can be provided in pair and installed on the right and left sides of a window  310  or the like. Further, it will be apparent to those skilled in the art that a plurality of optical transmitter modules  400 , optical contact modules  100 , optical fibers  200 , optical contact modules  100  and optical receiver modules  500  may be connected in parallel to one another to monitor a more wider range.  FIG. 7  shows a state where a plurality of optical transmitter modules  400  and optical receiver modules  500  are mounted within an optical transmitter module case  320 . 
     FIGS. 8   a  to  9   b  show portion C of  FIG. 7  and illustrate the process of connecting the optical fiber  200  to the optical transmitter module  400  using the optical contact module  100 . The optical transmitter module case  320  comprises an exterior case  322  and a cover  321 . For the connection of the optical fiber, a substrate  130  of the optical transmitter module and the optical device receiving member  20  are first installed on the exterior case  322 , then an O-ring  120  is fitted and the cover  321  is placed. At this moment, a light emitting device  132  is inserted into the optical device receiving portion  21  of the optical device receiving member  20 . Further, since the projection portion  24  formed on the optical device receiving member  20  is inserted into an insertion groove  134  formed in the substrate  130  to be installed within the exterior case  322 , as shown in  FIGS. 8   a  and  9   a,  the optical device receiving member  20  does not rotate when the optical fiber fixing cap  10  is rotated to be fastened to the optical device receiving member  20 . Alternatively, as shown in  FIGS. 8   b  and  9   b,  the pair of the projection portions  24  formed on the optical device receiving member  20  can be fastened to catching steps  135  formed on the optical transceiver module. Further, the O-ring  120  interposed between the cover  321  and the optical device receiving member  20  prevents raindrops from penetrating into the case. Next, a single optical fiber  220  is inserted into the through-hole of the optical fiber fixing cap  10  and the optical fiber supporting member  110  is fitted around the inserted end of the optical fiber that in turn is inserted into the optical fiber receiving portion  23  of the optical device receiving member  20  through a hole of the cover. Thereafter, the female threads formed on the inner surface of the optical fiber fixing cap  10  are screwed onto the male threads formed on the outer periphery of the optical fiber receiving portion  23 . At this time, the taper in the optical fiber fixing cap proceeds while pressing the tapered end of the optical fiber receiving portion  23 , thereby compressing and fixing the sheath of the optical fiber. 
   As shown in  FIGS. 9   a  and  9   b,  in a state where the optical fiber  200  has been assembled and fixed in such a manner, a core  210  is positioned close to the light emitting device  132  through the contact hole  22  to receive light or an optical signal emitted from the light emitting device  132 . Further, the optical fiber  200  passes through the optical fiber supporting member  110 , and the sheath  220  of the optical fiber is pressed and fixed within the optical fiber receiving portion  21  of the optical device receiving member  20  having the slits  27  by means of the optical fiber supporting member  110 , and then further compressed when the optical fiber fixing cap  10  is screwed onto the optical device receiving member. Therefore, the optical fiber  200  is fixed by compressing the sheath  220  without damaging the core  210  of the optical fiber  200 , the loss of the optical signal is avoided, and the introduction of noises and foreign materials from the outside is effectively prevented. Further, since the optical fiber can be cut and installed in place depending on the length required for an installation space, it is possible to variously change the length of the optical fiber depending on installation conditions. 
   INDUSTRIAL APPLICABILITY 
   As described above, the optical contact module of the present invention can easily connect optical fibers cut in desired lengths in place, and avoid optical loss and shield noises from the outside by completely sealing a contact portion. Further, the optical contact module of the present invention can prevent a security system from being damaged by allowing the optical fiber to be easily separated from the security system if external force exceeding a predetermined value is applied to the optical fiber, cause a damaged or antiquated optical fiber to be easily replaced from the outside, and fixedly support the optical fiber with appropriate elastic force without damage to a core or clad of the optical fiber. 
   It is intended that the embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. The scope of the present invention is defined only by the appended claims. Those skilled in the art can make various changes and modifications thereto without departing from its true spirit. Therefore, various changes and modifications obvious to those skilled in the art will fall within the scope of the present invention.