Abstract:
There is provided a high-speed transmission connector which is capable of achieving a match between characteristic impedances and excellent transmission characteristics for transmission of high-frequency signals and high-speed signals. The high-speed transmission connector comprises an insulator, and signal contacts and a shield contact held by the insulator. The signal contacts are arranged on opposite sides of the shield contact in a manner enclosed by a shield member continuous with the shield contact.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the invention  
           [0002]    This invention relates to a high-speed transmission connector for use in a communication device or the like, which is suitable for transmission of high-frequency signals.  
           [0003]    2. Description of the Prior Art  
           [0004]    [0004]FIG. 11 shows a conventional high-speed transmission connector in front view, while FIG. 12 shows the same in rear view. FIG. 13 is a cross-sectional view taken on line XIII-XIII of FIG. 11. FIG. 14 shows the FIG. 11 transmission connector in side view. FIG. 15 is a cross-sectional view taken on line XV-XV of FIG. 14, while FIG. 16 is a cross-sectional view taken on line XVI-XVI of FIG. 14. FIG. 17A is a side view of an upper-section shield contact, FIG. 17B a front view of the same, and FIG. 17C and FIG. 17D are a rear view and a plan view, respectively. Further, FIG. 18A is a side view of a middle-section shield contact, FIG. 18B a front view of the same, and FIG. 18C and FIG. 18D are a rear view and a plan view, respectively.  
           [0005]    The conventional connector includes an insulator  110  and a shield casing  120  attached to the insulator  110  in intimate contact with the same.  
           [0006]    The insulator  110  holds signal contacts  130   a ,  130   b , . . . (generically designated by reference numeral  130 ), the upper-section shield contact  140  and the middle-section shield contact  150 .  
           [0007]    A location plate  160  is fixedly secured to a rear face of the insulator  110  e.g. by press-fitting or the like. The location plate  160  has a lattice of contact through holes  161  formed therethrough. The contact through holes  161  are formed with respective tapered faces for guiding the contacts  130 ,  140 ,  150 .  
           [0008]    The signal contacts  130  and the shield contacts  140 ,  150  each have an intermediate portion thereof bent at a right angle (see FIGS. 17A and 18A).  
           [0009]    Each of the signal contacts  130  and the shield contacts  140 ,  150  has one end portion thereof inserted through a corresponding one of the contact through holes  161  and held by the location plate  160 .  
           [0010]    The front face (right side, as viewed in FIG. 14) of the insulator  110  is formed with receiving holes  111  for connection with a mating connector, not shown.  
           [0011]    Each of the signal contacts  130  and the shield contacts  140 ,  150  has the other end thereof disposed in a corresponding one of the receiving holes  111 .  
           [0012]    The signal contacts  130   a ,  130   b  and the signal contacts  130   c ,  130   d  are arranged on opposite sides of the shield contact  140  (see FIG. 13).  
           [0013]    The signal contacts  130   e ,  130   f  and the signal contacts  130   g ,  130   h  are arranged on opposite sides of the shield contact  150 .  
           [0014]    The signal contacts  130   a ,  130   b  adjacent to each other are used to transmit paired signals.  
           [0015]    In the above connector, however, since respective portions (designated by an arrow A in FIG. 14) of the contacts  130 ,  140  are exposed between the insulator  110  and the location plate  160 , characteristic impedances of the contacts, which are determined by inductances and capacitances of the respective contacts, become higher than a characteristic impedance applied to a transmission system for transmitting high-frequency signals and high-speed signals, which causes a mismatch between the characteristic impedances.  
           [0016]    Further, the characteristic impedances of an associated pair of signal contacts  130  (e.g. the signal contacts  130   a ,  130   b ) differ from each other due to difference in distance between the shield contacts  140 ,  150  and the respective corresponding signal contacts  130  (the impedance of a contact arranged at a location farther from a corresponding shield contact is higher than that of a contact arranged at a location closer to the shield contact), which causes variations in high-frequency characteristics of the associated pair of signal contacts.  
           [0017]    As a result, losses of high-frequency signals and high-speed signals due to the mismatch between the characteristic impedances are increased, and hence transmission characteristics are considerably degraded.  
         SUMMARY OF THE INVENTION  
         [0018]    It is an object of the invention to provide a high-speed transmission connector which is capable of maintaining a match between characteristic impedances and achieving excellent transmission characteristics for transmission of high-frequency signals and high-speed signals.  
           [0019]    To attain the above object, the present invention provides a high-speed transmission connector comprising:  
           [0020]    an insulator;  
           [0021]    at least one shield contact held by the insulator;  
           [0022]    at least one pair of signal contacts held by the insulation and each arranged on respective opposite sides of a corresponding one of the at least one shield contact; and  
           [0023]    a shield member enclosing the at least one pair of signal contacts and arranged continuous with the shield contact.  
           [0024]    According to this high-speed transmission connector, since portions of the signal contacts and the shield contact, which are exposed in the prior art, are enclosed by the shield member continuous with the shield contact, the signal contacts are shielded, whereby characteristic impedances of the respective signal contacts are reduced and become equal to each other.  
           [0025]    Preferably, the shield member is integrally formed with the shield contact.  
           [0026]    According to this preferred embodiment, since the shield member is integrally formed with the shield contact, it is possible to prevent an increase in number of component parts of the connector.  
           [0027]    The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 is a front view of a high-speed transmission connector according to an embodiment of the invention;  
         [0029]    [0029]FIG. 2 is a rear view of the FIG. 1 connector;  
         [0030]    [0030]FIG. 3 is a cross-sectional view taken on line III-III of FIG. 1;  
         [0031]    [0031]FIG. 4 is a vertical cross-sectional view of the FIG. 1 connector;  
         [0032]    [0032]FIG. 5 is a cross-sectional view taken on line V-V of FIG. 1;  
         [0033]    [0033]FIG. 6 is a cross-sectional view taken on line VI-VI of FIG. 1;  
         [0034]    [0034]FIG. 7A is a side view of an upper-section shield contact;  
         [0035]    [0035]FIG. 7B is a front view of the upper-section shield contact;  
         [0036]    [0036]FIG. 7C is a rear view of the upper-section shield contact;  
         [0037]    [0037]FIG. 7D is a plan view of the upper-section shield contact;  
         [0038]    [0038]FIG. 8A is a side view of a middle-section shield contact;  
         [0039]    [0039]FIG. 8B is a front view of the middle-section shield contact;  
         [0040]    [0040]FIG. 8C is a rear view of the middle-section shield contact;  
         [0041]    [0041]FIG. 8D is a plan view of the middle-section shield contact;  
         [0042]    [0042]FIG. 9 is a vertical cross-sectional view of a variation of the high-speed transmission connector according to the embodiment of the invention;  
         [0043]    [0043]FIG. 10 is a cross-sectional view taken on line X-X of FIG. 9;  
         [0044]    [0044]FIG. 11 is a front view of a conventional high-speed transmission connector;  
         [0045]    [0045]FIG. 12 is a rear view of the FIG. 11 connector;  
         [0046]    [0046]FIG. 13 is a cross-sectional view taken on line XIII-XIII of FIG. 11;  
         [0047]    [0047]FIG. 14 is a side view of the FIG. 11 connector with parts broken away;  
         [0048]    [0048]FIG. 15 is a cross-sectional view taken on line XV-XV of FIG. 14;  
         [0049]    [0049]FIG. 16 is a cross-sectional view taken on line XVI-XVI of FIG. 14;  
         [0050]    [0050]FIG. 17A is a side view of an upper-section shield contact;  
         [0051]    [0051]FIG. 17B is a front view of the upper-section shield contact;  
         [0052]    [0052]FIG. 17C is a rear view of the upper-section shield contact;  
         [0053]    [0053]FIG. 17D is a plan view of the upper-section shield contact;  
         [0054]    [0054]FIG. 18A is a side view of a middle-section shield contact;  
         [0055]    [0055]FIG. 18B is a front view of the middle-section shield contact;  
         [0056]    [0056]FIG. 18C is a rear view of the middle-section shield contact; and  
         [0057]    [0057]FIG. 18D is a plan view of the middle-section shield contact. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0058]    Next, the invention will now be described in detail with reference to drawings showing preferred embodiments thereof.  
         [0059]    [0059]FIG. 1 is a front view of a high-speed transmission connector according to an embodiment of the invention. FIG. 2 is a rear view of the same, and FIG. 3 is a cross-sectional view taken on line III-III of FIG. 3. FIG. 4 is a vertical cross-sectional view of the connector. FIG. 5 is a cross-sectional view taken on line V-V of FIG. 4, while FIG. 6 is a cross-sectional view taken on line VI-VI of FIG. 4.  
         [0060]    The connector is comprised of an insulator  10 , a shield casing  20 , a plurality of signal contacts  30   a ,  30   b . . . (generically designated by reference numeral  30 ), an upper-section shield contact  40  and a middle-section shield contact  50 .  
         [0061]    The shield casing  20  is attached to the front face of the insulator  10  in intimate contact therewith.  
         [0062]    A location plate  60  is fixedly secured to a rear face of the insulator  10  by press-fitting. The location plate  60  has a lattice of contact through holes  61  formed therethrough. The contact through holes  61  are formed with respective tapered faces  61   a  for guiding one end portions of the contacts  30 ,  40 ,  50 .  
         [0063]    The one end portion of each of the signal contacts  30  and the shield contacts  40 ,  50  is inserted through a corresponding one of the contact through holes  61  and held by the location plate  60 .  
         [0064]    The one end portions of the signal contacts  30  and the shield contacts  40 ,  50  are connected to a printed circuit board, not shown.  
         [0065]    The signal contacts  30  and the shield contacts  40 ,  50  each have a longitudinally intermediate portion thereof bent at a right angle.  
         [0066]    The front face (right side, as viewed in FIG. 4) of the insulator  10  is formed with a lattice of receiving holes  11  for connection with a mating connector, not shown.  
         [0067]    The signal contacts  30   a ,  30   b  and the signal contacts  30   c ,  30   d  are arranged in a row on the opposite sides of the shield contact  40  in an X direction.  
         [0068]    The signal contacts  30   e ,  30   f  and the signal contacts  30   g ,  30   h  are arranged in a row in the X direction on the opposite sides of the shield contact  50 .  
         [0069]    The adjacent pairs of signal contacts  30   a ,  30   b  and signal contacts  30   c ,  30   d , and the other paired signal contacts adjacent to each other are used to transmit paired signals.  
         [0070]    Each of the signal contacts  30  and the shield contacts  40 ,  50  has the other end portion thereof disposed in a corresponding one of the receiving holes  11 .  
         [0071]    The other end portions of the signal contacts  30  and the shield contacts  40 ,  50  are each formed to have a tuning fork shape.  
         [0072]    Next, the upper-section shield contact  40  and the middle-section shield contact  50  will be described.  
         [0073]    [0073]FIG. 7A shows the upper-section shield contact  40  in side view, FIG. 7B shows the same in front view, FIG. 7C shows the same in rear view, and FIG. 7D shows the same in plan view.  
         [0074]    The upper-section shield contact  40  has the intermediate portion thereof formed with first plate portions  41   a ,  41   b  extending in the X direction. The first plate portion  41   a  covers the signal contacts  30   b ,  30   a , while the first plate portion  41   b  covers the signal contacts  30   c ,  30   d  (see FIGS. 2 and 3).  
         [0075]    The first plate portion  41   a  has an end portion in the X direction which is formed with a generally rectangular second plate portion  42  extending in a Y direction perpendicular to the X direction in a manner shielding the signal contacts  30   e ,  30   i  (see FIG. 3).  
         [0076]    The second plate portion  42  extends in the Y direction to a location immediately close to the location plate  60 . The second plate portion  42  has part thereof supported by the insulator  10  (see FIG. 4).  
         [0077]    The first plate portions  41   a ,  41   b  have respective end portions in a Z direction perpendicular to the X direction and the Y direction (on a rear side of the connector) which are formed with third plate portions  44   a ,  44   b  extending in the Y direction via respective arcuate portions  43   a ,  43   b  continuous with the first plate portions  41   a ,  41   b . The third plate portions  44   a ,  44   b  extend to a location immediately close to the location plate  60  (see FIG. 4).  
         [0078]    Each of the third plate portions  44   a ,  44   b  has opposite ends in the X direction which are each bent toward the front of the connector (see FIGS. 4, 7A,  7 B).  
         [0079]    The first plate portions  41   a ,  41   b , the second plate portion  42 , the arcuate portions  43   a ,  43   b  and the third plate portions  44   a ,  44   b  form a shield member of the upper-section shield contact  40 .  
         [0080]    [0080]FIG. 8A shows the middle-section shield contact  50  in side view, FIG. 8B shows the same in front view, FIG. 8C shows the same in rear view, and FIG. 8D shows the same in plan view.  
         [0081]    The middle-section shield contact  50  has the intermediate portion thereof formed with first plate portions  51   a ,  51   b  extending in the X direction. The first plate portion  51   a  covers the signal contacts  30   f ,  30   e , while the first plate portion  51   b  covers the signal contacts  30   g ,  30   h  (see FIG. 3).  
         [0082]    The first plate portions  51   a ,  51   b  have respective end portions in the Z direction (on the rear side of the connector) which are formed with second plate portions  54   a ,  54   b  extending in the Y direction via respective arcuate portions  53   a ,  53   b  continuous with the first plate portions  51   a ,  51   b . The second plate portions  54   a ,  54   b  each extend to a location immediately close to the location plate  60  (see FIG. 4) The second plate portions  54   a ,  54   b  each have an end portion in the X direction which is bent toward the front of the connector (see FIGS. 8A, 8B).  
         [0083]    The first plate portions  51   a ,  51   b , the arcuate portions  53   a ,  53   b  and the second plate portions  54   a ,  54   b  form a shield member of the middle-section shield contact  50 .  
         [0084]    This construction makes it possible to change the distance between a signal contact and a shield member associated therewith to thereby change the characteristic impedance of the signal contact which is determined by inductance and capacitance thereof. For example, the characteristic impedance of the signal contact  30   a  arranged at a location farther from the shield contact  40  and the signal contact  30   b  arranged at a location closer to the same can be made equal with each other.  
         [0085]    Further, it is possible to shield the signal contacts  30   a  to  30   h  by the shield members, thereby reducing the characteristic impedance between the insulator  10  and the location plate  60 , where impedance mismatches occur.  
         [0086]    According to the present embodiment, it is possible to adjust variation in the high-frequency characteristic of each transmission line by the associated shield member to thereby adjust the characteristic impedance of the whole of the signal contacts  30  to a desired value (e.g. 50), so that the characteristic impedance can be matched, and hence improvement of the high-frequency characteristics (increase in the amount of insertion propagation, reduction of reflection loss, and reduction of propagation delay) can be achieved, which ensures excellent propagation characteristics for transmission of high-frequency signals and high-speed signals.  
         [0087]    Further, since the shield members are integrally formed with the respective shield contacts  40 ,  50 , it is possible to prevent man-hours for assembly from being increased due to an increase in number of component parts of the connector, thereby reducing manufacturing costs.  
         [0088]    Although in the above embodiment, the shield members are integrally formed with the respective shield contacts  40 ,  50 , the former may be formed as members separate from the latter. In this case, first, the contacts  30 ,  40 ,  50  are mounted to the insulator  10 , and then the shield members are press-fitted into the insulator  10  for contact with the shield contacts  40 ,  50 . According to this construction, the construction of a die can be simplified, which facilitates manufacturing of the die.  
         [0089]    Further, the shield members may be each formed to have a cylindrical shape. In this case, signal contacts are disposed within each of the cylindrical shield members to form a quasi-coaxial structure.  
         [0090]    Moreover, impedance matching for a cable for wiring the signal contacts may be achieved by the shield members of the shield contacts.  
         [0091]    [0091]FIG. 9 is a variation of the vertical cross-sectional view of a high-speed transmission connector according to the embodiment of the invention, and FIG. 10 is a cross-sectional view taken on line X-X of FIG. 9. Component parts and elements similar to those of the above embodiment are designated by identical reference numerals, and detailed description thereof is omitted.  
         [0092]    An upper-section shield contact  80  has an intermediate portion thereof formed with first plate portions  81   a ,  81   b  extending in the X direction. The first plate portion  81   a  covers signal contacts  30   b ,  30   a , while the first plate portion  81   b  covers signal contacts  30   c ,  30   d  (see FIG. 10). The signal contacts  30   b ,  30   a ,  30   c ,  30   d  are not seen in FIG. 10.  
         [0093]    The first plate portions  81   a ,  81   b  have respective one end portions in the Z direction (on the front side of the connector) which are formed, respectively, with generally rectangular second plate portions  82   a ,  82   b  extending in the Z direction. The second plate portions  82   a ,  82   b  are fixedly secured to the insulator  10  by press-fitting (see FIGS. 9 and 10).  
         [0094]    The first plate portions  81   a ,  81   b  have respective other end portions in the Z direction (on the rear side of the connector) which are formed with third plate portions  84   a ,  84   b  extending in the Y direction via respective arcuate portions  83   a ,  83   b  continuous with the first plate portions  81   a ,  81   b . The third plate portions  84   a ,  84   b  are fixedly secured to a location plate  70  e.g. by press-fitting (see FIG. 9).  
         [0095]    The first plate portions  81   a ,  81   b , the second plate portion  82   a ,  82   b , the arcuate portions  83   a , 83   b  and the third plate portions  84   a ,  84   b  form a shield member of the upper-section shield contact  80 .  
         [0096]    The construction of a middle-section shield contact  90  is generally identical to that of the upper-section shield contact  80  except that the middle-section shield contact  90  has first and third plate portions shorter than those of the upper-section shield contact  80 , and hence detailed description thereof is omitted.  
         [0097]    The location plate  70  is formed with stepped portions such that the height of the location plate  70  is increased step by step in a direction away from the insulator  10 . Each of the stepped portion is formed with contact through holes  71 . The contact through holes  71  are formed in lattice, as viewed in plan view. The contact through holes  71  has respective tapered faces  71   a  formed for guiding one end portions of the corresponding contacts  30 ,  80 ,  90 , respectively.  
         [0098]    This variation can provide the same effects as obtained by the above embodiment.  
         [0099]    It is further understood by those skilled in the art that the foregoing is the preferred embodiment of the invention, and that various changes and modification may be made without departing from the spirit and scope thereof.