Abstract:
An apparatus for optical fiber connection is provided, including a shell base and at least an optical fiber coupling tube. The inner shape and the outer shape of the shell base are made according to the different types of optical fiber connection apparatus specifications. The optical fiber coupling tube is fixed to the inside of the shell base. The optical fiber tube includes a hard tube wall along the axis of the tube and at least a deformable tube wall. The deformable tube wall is resilient and can be slightly deformed and restored to original shape. When used for connecting optical fibers, the present invention provides precise positioning and the optical signal loss and pulling torque are all within specifications.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to an apparatus for optical fiber connection, and more specifically to a special design inside the apparatus structure so as to enable the structure with appropriate firmness and capability to restore to original state to achieve the precision positioning, convenient operation and suitable fixation required for optical fiber connection. 
       BACKGROUND OF THE INVENTION 
       [0002]      FIG. 1  shows a dissected view of a conventional SC-type optical fiber connector. The optical fiber connector includes two shells  11 ,  12 , two buckle units  13 ,  14  and a ceramic sleeve  15 . The vertical side of buckle units  13  includes two facing buckle plates  131 , and a hollow tube  132 . The corresponding locations on buckle unit  14  also include two buckle plates  141  and a tube  142 . Ceramic sleeve  15  includes a tiny trench  151  along the axis direction so that ceramic sleeve  15  has the capability of slight deformation and restoring to original shape. When assembled, ceramic sleeve  15  is placed inside tubes  132 ,  142 , buckle units  13 ,  14  are aligned, buckled and fastened, and shells  11 ,  12  are sheathed and fixed to the outer side of buckle units  13 ,  14  to form an optical fiber connector. The characteristic of the structure is that: when the optical fiber ferrule is inserted from the two ends of ceramic sleeve  15 , trench  151  enables ceramic sleeve to slightly deform the inner hole or enlarge the inner hole to allow the optical fiber ferrule to insert repeatedly. When ceramic sleeve  15  restores to original shape, the two optical fibers are positioned and aligned. However, this structure has the following disadvantages: 
         [0003]    1. The number of parts is large so that the assembly process is complex and time-consuming; 
         [0004]    2. The manufacturing cost is high because the ceramic sleeve must be considerable precision; and 
         [0005]    3. More molds must be designed since the number of parts required is large; and then parts are manufactured and stored separately before assembled. This also leads to high manufacturing cost. 
         [0006]    Therefore, it is imperative to provide an apparatus for optical fiber connection to overcome the aforementioned disadvantages. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary object of the present invention is to provide an apparatus for optical fiber connection that is low in manufacturing cost and allows precision positioning. The internal structure of the apparatus uses a specially designed optical fiber coupling tube for alignment and coupling of the optical fiber ferrule. In addition, the optical fiber coupling tube can be manufactured by injection molding with a single material so as to greatly reduce the manufacturing cost. When the apparatus is in use, the apparatus can meet the international specification of optical signal loss and pulling torque after connecting optical fibers. 
         [0008]    Another object of the present invention is to provide an apparatus for optical fiber connection for a wide range of applications, such as, SC-type optical fiber connector and LC-type optical fiber connector. In addition, the present invention is not limited to one-to-one optical fiber connection. The apparatus of the present invention is also applicable to many-to-many optical fiber connections. 
         [0009]    Yet another object of the present invention is to provide an apparatus for optical fiber connection having a small number of parts and easy to manufacture. Comparing the SC-type optical fiber connection apparatus of the present invention with conventional SC-type optical fiber connector shows that the number of parts of the present invention can be reduced to three, two or even one, that is a great reduction when compared to the conventional connector having five parts. This also leads to save of manufacturing cost and assembly time. Furthermore, the product is more competitive in market as no expensive ceramic sleeve is required in the present invention. 
         [0010]    To achieve the above objects, the apparatus for optical fiber connection of the present invention includes a shell base and at least an optical fiber coupling tube fixed inside the shell base. The inner shape and the outer shape of the shell base are made according to the different types of optical fiber connection apparatus. The optical fiber coupling tube is fixed to the inside of the shell base at the middle section so that the optical fiber tube is hanging and distributive inside the shell base. The optical fiber tube includes a hard tube wall along the axis of the tube and at least a deformable tube wall. The deformable tube wall is resilient and can be slightly deformed and restored to original shape. In addition, the structure of the optical fiber coupling tube can be divided into two types. The first type is an optical fiber coupling tube formed commonly with the hard tube wall and the deformable tube wall, and the second type is an optical fiber coupling tube formed commonly with near-round hard tube wall and deformable tube wall located inside the hard tube wall. 
         [0011]    Furthermore, to facilitate the easy insertion of the optical fiber ferrule into the two ends of the optical fiber coupling tube, the present invention can also allow the optical fiber coupling tube to keep an offset of 2°. The application is as follows: the middle section of the optical fiber coupling tube is fixed by a fixed plate with at least a trench. The distribution of the trench is close to the engagement location of the fixed plate and the optical fiber coupling tube. 
         [0012]    The foregoing and other objects, features, aspects and advantages of the present invention will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention can be understood in more detail by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein: 
           [0014]      FIG. 1  shows a dissected view of a conventional optical fiber connector; 
           [0015]      FIG. 2  shows a top view of a first embodiment of the present invention; 
           [0016]      FIG. 3  shows a partial cross-section view of the first embodiment of the present invention; 
           [0017]      FIG. 4  shows a partial cross-section view of the second embodiment of the present invention; 
           [0018]      FIG. 5  shows a partial cross-section view of the third embodiment of the present invention; 
           [0019]      FIG. 6  shows a partial cross-section view of the fourth embodiment of the present invention; 
           [0020]      FIG. 7A  shows a partial cross-section view of the fifth embodiment of the present invention; 
           [0021]      FIG. 7B  shows a side view of the fifth embodiment of the present invention; 
           [0022]      FIG. 8  shows a dissected view of the first embodiment of the present invention; 
           [0023]      FIG. 9  shows a dissected view of another embodiment of the present invention; 
           [0024]      FIG. 10  shows a top view of a 2-to-2 optical fiber connection apparatus of the present invention; 
           [0025]      FIG. 11  shows a partial cross-sectional schematic view of an LC-type optical fiber connection apparatus according to the present invention; and 
           [0026]      FIG. 12  shows a top view of an LC-type optical fiber connection apparatus according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]      FIG. 2  and  FIG. 3  show respectively a top view and a cross-sectional view of the present invention applied to a one-to-one optical fiber connection apparatus according to the present invention. An optical fiber connection apparatus  2  of the present invention includes a shell base  3  and at least an optical fiber coupling tube  4 . The inner shape and the outer shape of shell base  3  are made to meet requirements of different types of optical fiber connection apparatus. The present embodiment is an SC-type optical fiber connection apparatus; hence, the structure of shell base  3  includes a shell  31 , a fixed plate  32  and two buckle sets  33 . Fixed plate  32  is located inside shell  31  at the middle section, and is fixed to the outer wall of the middle section of optical fiber coupling tube  4 . Two buckle sets  33  are located respectively on the two profile sides of the back of fixed plate  32 . Buckle set  33  includes two facing buckle plates  331 ,  332 . Buckle plates  331 ,  332  are resilient, and have the shape and structure made to match the optical fiber ferrule. Shell base  3  is similar to the conventional structure, and the detailed description is omitted here. The key feature of the present invention is optical fiber coupling tube  4 . The outer wall of optical fiber coupling tube  4  is engaged to fixed plate  32  at the middle section so that optical fiber coupling tube  4  is distributed on both sides of fixed plate  32  in a hanging arm manner. Optical fiber coupling tube  4  includes a hard tube wall  41  along the axis of the coupling tube and at least a deformable tube wall  42 . The inside of optical fiber coupling tube  4  is a hollow tube for optical fiber ferrule coupling. Deformable tube wall  42  is resilient and can be slightly deformed and restored to original shape. Optical fiber coupling tube  4  is made of polymer material, such as, synthesized plastic, synthesized rubber, synthesized fiber, synthesized resin, and so on. 
         [0028]    The theory behind the present invention is that the optical fiber ferrule is inserted into optical fiber coupling tube  4 , deformable tube wall  42  slightly deforms the inner hole to accommodate the continuous insertion of optical fiber ferrule. Then, the resilience of deformable tube wall  42  will restore to original shape to achieve the fastening holding of coupled optical fiber ferrules. In addition, the restoring capability of deformable tube wall  42  can also push the optical fiber ferrule towards the inner wall of hard tube wall  41 . AT this point, the baseline surface of the optical fiber ferrule coupling is the inner wall of hard tube wall  41 . In this manner, the two optical fiber ferrules inserted from two ends of optical fiber coupling tube  4  will be aligned on the same center axis to assure the correct positioning and coupling of the optical fibers. 
         [0029]    The above description shows the importance of deformable tube wall  42  of optical fiber coupling tube  4 . But how does deformable wall tube  42  achieve the capability of slight deformation and restoration to original shape? The following provides a plurality of embodiments. As shown in  FIG. 3 , optical fiber coupling tube  4  includes a hard tube wall  41  and deformable tube wall  42 . The thickness of deformable tube wall  42  is less than the thickness of hard tube wall  41 , and a concave trench  43  is located on the tube wall of hard tube wall  41  close to deformable tube wall. Concave trench  43  can be formed on at least one of the locations of inner wall or outer wall of hard tube wall  41 , and is distributed along the axial direction of hard tube wall  41 . The present embodiment includes two concave trenches on the inner wall of hard tube wall  41 . Because hard tube wall  41  is thicker, made of hard material and not deformable, the use of thinner deformable tube wall  42  and concave trench  43  will enable deformable tube wall  42  with the capability to slightly deform and restore to original shape. In addition, the size of inner hole formed by hard tube wall  41  and deformable tube wall  42  is less than or equal to the size of the optical fiber ferrule to be connected. 
         [0030]    In the above embodiment, optical fiber coupling tube  4  also includes two important features, thinner deformable tube wall  42  and axial direction concave trenches  43 . But the present invention is not limited to the above embodiment. For example, the optical fiber coupling tube can also include a thinner deformable tube wall without concave trenches. Alternatively, the optical fiber coupling tube can have hard tube wall and deformable tube wall of equal thickness, but having at least a concave trench at the locations as the above embodiment. In this manner, the concave trench allows the location of the deformable tube wall to change. 
         [0031]    Because the main feature of the present invention is the optical fiber coupling tube, the following embodiments only show fixed plate  32  and optical fiber coupling tube.  FIG. 4  shows a second embodiment of the present invention. As shown in  FIG. 4 , optical fiber coupling tube  4 A includes hard tube wall  41  and two deformable tube walls  42 , all distributed along the axial direction so as to form a round inner hole inside the tube. Deformable tube wall  42  must be thinner than hard tube wall  41 . The present embodiment includes three concave trenches  43 , where two are formed at the location on hard tube wall  41  close to deformable tube wall  42 , and one is formed between two deformable tube walls  42 . To maintain the strength of hard tube wall  41 , the part of the circumference of optical fiber coupling tube  4 A formed by hard tube wall  41  is preferably at least more than half of the total circumference. 
         [0032]      FIG. 5  shows a third embodiment of the present invention. As shown in  FIG. 5 , optical fiber coupling tube  4 B includes a hard tube wall  41 B and at least a deformable tube wall  42 B. Deformable tube wall  42 B is located inside hard tube wall  41 B. In the present embodiment, the shape of the inner hole inside optical fiber coupling tube  4 B is formed by hard tube wall  41 B and deformable tube wall  42 B. Hard tube wall  41 B is a round tube wall formed with a thick wall region  411  and thin wall region  412 , where deformable tube wall  42 B is located at the inner wall of thin wall region  412 . A gap exists between thin wall region  412  and some parts of deformable tube wall  42 B so that deformable tube wall is able to slightly deform and restore to original shape. The present embodiment includes two deformable tube walls  42 B. In addition, the size of the inner hole formed by thick wall region  411  of hard tube wall  41 B and two deformable tube walls  42 B must be less than or equal to the size of the optical fiber ferrule to connect. 
         [0033]      FIG. 6  shows a fourth embodiment of the present invention. As shown in  FIG. 6 , optical fiber coupling tube  4 C is formed by a hard tube wall  41 C and three deformable tube walls  42 B, with all deformable tube walls  42 B distributed inside hard tube wall  41 C along the axial direction. In the present embodiment, the inner hole inside optical fiber coupling tube  4 C is formed by three deformable tube walls  42 B. Hard tube wall  41 C of the present embodiment is a thin tube with strength and not deformable. Deformable tube walls  42 B are engaged to the inside of hard tube wall  41 C with gap between inner wall of hard tube wall  41 C and some part of deformable tube walls  42 B to allow slight deformation and restoration to original shape. A special condition of the present embodiment is that the restoration force of three deformable tube walls  42 B must pass the center of the tube because the inner hole is formed by the three deformable tube walls so that the optical fiber ferrules inserted at two ends of optical fiber coupling tube can be aligned on the same center line. 
         [0034]      FIG. 7A  and  FIG. 7B  show a fifth embodiment of the present invention. The object of the present embodiment is to allow the two ends of optical fiber coupling tube  4  for  2 ° offset to the right and left along the center line as the baseline. In the present embodiment, the outer wall of optical fiber coupling tube  4  is still engaged to fixed plate  32 . Fixed plate  32  includes a plurality of trenches  321  penetrating fixed plate  32  and in an arc shape. The distribution of trenches  321  is located close to the joint of fixed plate  3  and optical fiber coupling tube  4 . The present embodiment includes three trenches  321  uniformly distributed on fixed plate  32  in a broken ring shape. In this manner, the area of direct engagement between fixed plate  32  and optical fiber coupling tube  4  decreases so that entire optical fiber coupling tube  4  allows an offset of 2°. Also, the design of trenches  321  is applicable to the embodiments of  FIGS. 4-6 . 
         [0035]      FIG. 8  shows a dissected view of the present invention. To facilitate the ease of manufacturing, the present invention can be assembled by three parts that can be manufactured separately, where the first part includes fixed plate  32 , two buckle sets  33  and optical fiber coupling tube  4 , and shell  31  includes a first shell part  311  and second shell part  312 . The above three parts are all manufactured with injection molding. In assembly, the first part is placed in the middle. Then, the second and third parts are aligned to engage. The parts can be further glued together with glue or high frequency gluing technology. 
         [0036]      FIG. 9  shows a dissected view of another embodiment of the present invention. In this embodiment, the first part includes fixed plate  32 , two buckle sets  33  and optical fiber coupling tube  4 , and the second part is shell  31 A. Shell  31 A is a hollow shell. The above two parts can both be manufactured with injection molding. This embodiment shows that the present invention can use to parts to realize an apparatus for optical fiber connection. As shown in  FIG. 8  and  FIG. 9 , the apparatus for optical fiber connection of the present invention can include either two or three parts, depending on the design. Furthermore, the designer can integrate the fixed plate and optical fiber coupling tube as the first part and the buckle sets as the second part, or even change the shape of the shell so that the entire apparatus for optical fiber connection can be made as a single part to be manufactured with injection molding. Hence, the present invention is not limited to any specific number of parts to form the optical fiber connection apparatus. 
         [0037]      FIG. 10  shows a schematic view of a 2-to-2 SC-type optical fiber connection apparatus according to the present invention. In the present embodiment, optical fiber connection apparatus  2 A is of 2-to-2 specification, and the shape of shell base  3 A is different, for example, shell base  3 A includes four buckle sets  33 . Additionally, the embodiment includes two optical fiber coupling tubes. As aforementioned, the present invention is applicable to both one-to-one and many-to-many applications. 
         [0038]      FIG. 11  and  FIG. 12  show a partial cross-sectional view and a tope view of a one-to-one LC-type optical fiber connection apparatus according to the present invention. Shell base  3 B of the present embodiment is of LC-type specification, and therefore, does not include buckle sets. Optical fiber coupling tube  4  is still fixed to the inside of shell base  3 B at the middle section with a fixed plate  32 . Similarly, the present invention is also applicable to a 2-to-2 LC-type optical fiber connection apparatus. 
         [0039]    The aforementioned embodiments show that the present invention is applicable to various types of optical fiber connection apparatuses, such as, SC-type and LC-type, one-to-one and many-to-many, and so on. The shape of the shell base can be designed to match the respective specification. The important commonality is that each optical fiber connection apparatus must include at least an optical fiber coupling tube of the present invention. 
         [0040]    In summary, the optical fiber connection apparatus of the present invention includes an optical fiber coupling tube. The inside of optical fiber coupling tube is a hollow tube for optical fiber coupling. The optical fiber coupling tube is fixed to the inside of shell base with a fixed plate at the middle section on the outside. The optical fiber coupling tube is formed by hard tube wall and deformable tube wall, distributed along the axial direction. The deformable tube wall allows the inner hole inside the tube to deform to facilitate easy insertion of rigid optical fiber ferrule. The capability to restore to original shape of the deformable tube wall provides strong holding onto the inserted optical fiber ferrule. The hard tube wall provides a baseline for the optical fiber ferrule to be pushed towards to the baseline by the restoration force of the deformable tube wall so that the two optical fiber cables to connect can be aligned to the same center line. The present invention is easy to operate, and provides strong holding and precise positioning. 
         [0041]    Although the present invention has been described with reference to the preferred embodiments, it will be understood that the invention is not limited to the details described thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.