Patent Publication Number: US-9847595-B2

Title: Electrical receptacle connector

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority under 35 U.S.C. §119(a) to Patent Application No. 201521079338.7 filed in China, P.R.C. on Dec. 23, 2015, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The instant disclosure relates to an electrical connector, and more particular to an electrical receptacle connector. 
     BACKGROUND 
     Generally, Universal Serial Bus (USB) is a serial bus standard to the PC architecture with a focus on computer interface, consumer and productivity applications. The existing Universal Serial Bus (USB) interconnects have the attributes of plug-and-play and ease of use by end users. Now, as technology innovation marches forward, new kinds of devices, media formats and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience that users have come to expect. In addition, the demand of a higher performance between the PC and the sophisticated peripheral is increasing. The transmission rate of USB 2.0 is insufficient. Therefore, faster serial bus interfaces such as USB 3.0, are developed, which may provide a higher transmission rate so as to satisfy the need of a variety devices. 
     The appearance, the structure, the contact ways of terminals, the number of terminals, the pitches between terminals (the distances between the terminals), and the pin assignment of terminals of a conventional USB type-C electrical connector are totally different from those of a conventional USB electrical connector. A conventional USB type-C electrical receptacle connector includes a plastic core, upper and lower receptacle terminals held on the plastic core, and an outer iron shell circularly enclosing the plastic core. 
     SUMMARY OF THE INVENTION 
     However, gaps may be formed between the outer iron shell and the plastic core of the conventional USB type-C connector. Commonly, waterproof glues are filled into the gaps for sealing and preventing water moist from penetrating into the interior of the connector. Nevertheless, the inner wall of the outer iron shell is smooth, and the waterproof glues will penetrate into the interior of the connector rather than attaching onto the inner wall of the outer iron shell when the waterproof glues are fed into the gaps. As a result, the gaps cannot be sealed properly and penetration of water moist still occurs. Therefore, how to solve the aforementioned problem is an issue. 
     In view of this, an embodiment of the instant disclosure provides an electrical receptacle connector. The electrical receptacle connector comprises a metallic shell, an insulated housing, a plurality of first receptacle terminals, a plurality of second receptacle terminals, and a first texture region. The metallic shell comprises a shell body and a receptacle cavity defined through the shell body. Two ends of the shell body are respectively formed as a front end and a rear end. The insulated housing is received in the receptacle cavity. The insulated housing comprises a base portion and a tongue portion extending from the one end of the base portion. An inner gap is formed between an inner wall of the shell body at the rear end and the base portion. The first receptacle terminals comprise a plurality of first signal terminals, at least one first power terminal, and at least first ground terminal. The first receptacle terminals are held in the base portion and the tongue portion. The second receptacle terminals comprise a plurality of second signal terminals, at least one second power terminal, and at least one second ground terminal. The second receptacle terminals are held in the base portion and the tongue portion. The first texture region is annularly formed on the inner wall of the shell body. The first texture region corresponds to a periphery of an outer wall of the base portion and is distributed within the inner gap. 
     In one embodiment, an end portion of the shell body at the rear end is protruding from a lateral surface of the base portion to form a first glue recess. In addition, the electrical receptacle connector further comprises a sealing member filled in the first glue recess. The sealing member penetrates into the inner gap and fills the first texture region. Moreover, the metallic shell further comprises a case circularly enclosing the shell body. 
     In one embodiment, the electrical receptacle connector further comprises an enveloping shell circularly enclosing the shell body. An end portion of the enveloping shell corresponding to the rear end of the shell body is protruding from the lateral surface of the base portion to form a second glue recess. Furthermore, the electrical receptacle connector further comprises a sealing member filled in the second glue recess. The sealing member penetrates into the inner gap and fills the first texture region. 
     In one embodiment, an outer gap is formed between an inner wall of the enveloping shell corresponding to the rear end of the shell body and an outer wall of the shell body. Furthermore, the electrical receptacle connector further comprises a second texture region. The second texture region is annularly formed on an outer wall of the shell body. The second texture region corresponds to an inner wall of the enveloping shell and is distributed within the outer gap. Moreover, the electrical receptacle connector further comprises a sealing member filled in the second glue recess. The sealing member penetrates into the outer gap and fills the second texture region. 
     Another embodiment of the instant disclosure provides an electrical receptacle connector. The electrical receptacle connector comprises a metallic shell, an insulated housing, a plurality of first receptacle terminals, a plurality of second receptacle terminals, and an enveloping shell. The metallic shell comprises a shell body and a receptacle cavity defined through the shell body. Two ends of the shell body are respectively formed as an front end and a rear end. The insulated housing is received in the receptacle cavity. The insulated housing comprises a base portion and a tongue portion extending from one end of the base portion. The base portion is located at an end portion of the shell body. The rear end of the shell body is protruding from a lateral surface of the base portion to form a first glue recess. The first receptacle terminals are held in the base portion and the tongue portion. The second receptacle terminals are held in the base portion and the tongue portion. The enveloping shell circularly encloses the shell body. An end portion of the enveloping shell corresponding to the rear end of the shell body is protruding from the lateral surface of the base portion to form a second glue recess. The second glue recess comprises the first glue recess. 
     As above, the first texture region makes the inner wall of the metallic shell form a rough surface, so that the sealing member can attach onto the first texture region efficiently. Therefore, the sealing member does not overflow into the front portion of the receptacle cavity, and the inner gap can be sealed by the sealing member properly. Hence, the first texture region allows the sealing member to attach onto the inner wall of the shell body, and the sealing member can cover the inner gap completely to provide a reliable waterproof performance. Furthermore, the second texture region make the outer wall of the shell body form a rough surface, so that the sealing member can attach onto the second texture region efficiently. Therefore, the sealing member does not overflow into the front portion of the receptacle cavity, and the outer gap can be sealed by the sealing member properly. Hence, the second texture region allows the sealing member to attach onto the outer wall of the shell body, and the sealing member can cover the outer gap completely to provide a reliable waterproof performance. 
     Furthermore, the first receptacle terminals and the second receptacle terminals are arranged upside down, and the pin-assignment of the flat contact portions of the first receptacle terminals is left-right reversal with respect to that of the flat contact portions of the second receptacle terminals. Accordingly, the electrical receptacle connector can have a 180-degree symmetrical, dual or double orientation design and pin assignments which enables the electrical receptacle connector to be mated with a corresponding plug connector in either of two intuitive orientations, i.e. in either upside-up or upside-down directions. Therefore, when an electrical plug connector is inserted into the electrical receptacle connector with a first orientation, the flat contact portions of the first receptacle terminals are in contact with upper-row plug terminals of the electrical plug connector. Conversely, when the electrical plug connector is inserted into the electrical receptacle connector with a second orientation, the flat contact portions of the second receptacle terminals are in contact with the upper-row plug terminals of the electrical plug connector. Note that, the inserting orientation of the electrical plug connector is not limited by the electrical receptacle connector of the instant disclosure. 
     Detailed description of the characteristics and the advantages of the instant disclosure are shown in the following embodiments. The technical content and the implementation of the instant disclosure should be readily apparent to any person skilled in the art from the detailed description, and the purposes and the advantages of the instant disclosure should be readily understood by any person skilled in the art with reference to content, claims, and drawings in the instant disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The instant disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus not limitative of the instant disclosure, wherein: 
         FIG. 1  illustrates a perspective view of an electrical receptacle connector according to a first embodiment of the instant disclosure; 
         FIG. 2  illustrates an exploded view of the electrical receptacle connector; 
         FIG. 3  illustrates a front view of the electrical receptacle connector; 
         FIG. 4  illustrates a schematic configuration diagram of the receptacle terminals of the electrical receptacle connector shown in  FIG. 3 ; 
         FIG. 5  illustrates another exploded view of the electrical receptacle connector; 
         FIG. 6  illustrates another perspective view of the electrical receptacle connector; 
         FIG. 7  illustrates an enlarged lateral view of the first texture region of the electrical receptacle connector of the first embodiment; 
         FIG. 8  illustrates an exploded view of an electrical receptacle connector according to a second embodiment of the instant disclosure; 
         FIG. 9  illustrates an enlarged lateral view of the first texture region of the electrical receptacle connector of the second embodiment; 
         FIG. 10  illustrates another enlarged lateral view of the electrical receptacle connector having a second texture region; 
         FIG. 11  illustrates an exploded view of an electrical receptacle connector according to a third embodiment of the instant disclosure; and 
         FIG. 12  illustrates an enlarged view of the electrical receptacle connector of the third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , illustrating an electrical receptacle connector of a first embodiment of the instant disclosure.  FIG. 1  illustrates a perspective view of an electrical receptacle connector according to the first embodiment of the instant disclosure. In this embodiment, the electrical receptacle connector  100  is mounted on a circuit board in a sinking type for performing a low profile configuration. That is, one side of the circuit board is cut to form a notch, and the electrical receptacle connector  100  is mounted within the notch and a side portion of the circuit board, but embodiments are not limited thereto. In this embodiment, the electrical receptacle connector  100  can provide a reversible or dual orientation USB Type-C connector interface and pin assignments, i.e., a USB Type-C receptacle connector. In this embodiment, the electrical receptacle connector  100  comprises a metallic shell  11 , an insulated housing  2 , a plurality of first receptacle terminals  31 , a plurality of second receptacle terminals  41 , and a first texture region  51 . 
     Please refer to  FIG. 2 , illustrating an exploded view of the electrical receptacle connector of the first embodiment. The metallic shell  11  is a hollowed shell, and the metallic shell  11  comprises a shell body  121  and a receptacle cavity  112  formed in and defined through the shell body  121 . Two ends of the shell body  121  are respectively formed as a front end  115  and a rear end  116 . The front end  115  is adapted to be mated with an electrical plug connector. Tail portions  316  of the first receptacle terminals  31  and tail portions  416  of the second receptacle terminals  41  are located near the rear end  116  and adapted to be soldered on a circuit board. In this embodiment, the shell body  121  may be a tubular member and the receptacle cavity  112  is formed in the tubular member. The metallic shell  11  may be formed by a multi-piece member; in such embodiment, the metallic shell  11  comprises a case  124  circularly enclosing the shell body  121 . The shell body  121  may be a seamless and hollowed tubular member formed by deep drawing technique; alternatively, the shell body  121  may be a seamed and hollowed tubular member formed by bending a metallic plate. In addition, the case  124  may be a semi-tubular member with a U-shape cross section, and the case  124  covers the top and the two sides of the shell body  121  to be formed as an outer shell structure. In addition, an insertion opening  113  with oblong shaped is formed on the front end  115  of the shell body  121 , and the insertion opening  113  communicates with the receptacle cavity  112 . 
     Please refer to  FIG. 2 . In this embodiment, the insulated housing  2  is received in the receptacle cavity  112 . The insulated housing  2  comprises a base portion  21  and a tongue portion  22 . In this embodiment, the tongue portion  22  is extending from the base portion  21 . An inner gap  211  is formed between an inner wall  121   a  of the shell body  121  at the rear end  116  of the shell body  121  and the base portion  21 . 
     Please refer to  FIG. 2 . In this embodiment, the insulated housing  2  further comprises a first portion and a second portion. The second portion is assembled with the first portion to form the insulated housing  2 . That is, the first portion and the second portion can be assembled with each other to form the base portion  21  and the tongue portion  22 . In addition, the base portion  21  may be integrally formed with the tongue portion  22  by injection molding. Furthermore, a shielding plate  7  is assembled or molded inside the base portion  21  and the tongue portion  22 . In this embodiment, the first portion is insert-molded with the first receptacle terminals  31 , and the second portion is insert-molded with the second receptacle terminals  41 . 
     Please refer to  FIGS. 2, 5, and 6 .  FIG. 5  illustrates another exploded view of the electrical receptacle connector of the first embodiment.  FIG. 6  illustrates another perspective view of the electrical receptacle connector of the first embodiment. In this embodiment, the tongue portion  22  is located at a front portion of the receptacle cavity  112 , and the base portion  21  is located at a rear portion of the receptacle cavity  112 . An end portion  1211  of the shell body  121  at the rear end  116  is protruded from a lateral surface of the base portion  21  to form a first glue recess  123 . In other words, the rear lateral surface of the base portion  21  does not flush with the rear edge of the shell body  121 , and a cross section of the base portion  21  and the shell body  121  forms an E shape without middle bar when the base portion  21  is received in the receptacle cavity  112 . 
     Please refer to  FIGS. 2 and 3 .  FIG. 3  illustrates a front view of the electrical receptacle connector of the first embodiment. The tongue portion  22  has two opposite surfaces, one is a first surface  221 , and the other is the second surface  222 . In addition, a front lateral surface  223  of the tongue portion  22  is respectively connected with the first surface  221  and the second surface  222  and is close to the insertion opening  113 . In other words, the front lateral surface  223  is near the insertion opening  113  and perpendicularly connected to the first surface  221  and the second surface  222 , respectively. 
     Please refer to  FIGS. 5 and 6 . In this embodiment, the insulated housing  2  further comprises a rear plate  25  extended outward from the middle portion of the rear of the base portion  21 . In addition, the rear plate  25  is protruded out of the receptacle cavity  112  from the first glue recess  123 , so that the first glue recess  123  forms an annular channel. The bottom surface of the annular channel is formed by the surface of the base portion  21 , and the lateral surfaces of the annular channel are formed by the rear plate  25  and the shell body  121 , respectively. The base portion  21 , the rear plate  25 , and the shell body together define the annular channel. 
     Please refer to  FIGS. 5 to 7 .  FIG. 7  illustrates an enlarged lateral view of the first texture region of the electrical receptacle connector of the first embodiment. In this embodiment, the first texture region  51  is annularly formed on the inner wall  121   a  of the shell body  121 . The first texture region  51  corresponds to a periphery of an outer wall of the base portion  21  and is distributed within the inner gap  121   a . The first texture region  51  may be patterns formed by pressing techniques and may be aligned equidistantly or unequidistantly. The first texture region  51  may be aligned parallel (not overlapped) or nonparallel (overlapped), and the shape of the first texture region  51  may be rectangle, triangle, etc. It is understood that, the width of the first texture region  51  and the roughness of the pattern on the first texture region  51  can be altered according to glues with different viscosities. 
     Please refer to  FIGS. 5 to 7 . The first glue recess  123  is for filling a sealing member  8  in liquid state. The sealing member  8  penetrates the annular channel and makes the rear portion of the insulated housing  2  be filled with the sealing member  8 , so that the inner gap  211  is completely sealed by the sealing member  8 . In other words, the sealing member  8  is filled in the first glue recess  123 , and the sealing member  8  penetrates into the inner gap  211  and fills the first texture region  51 . The first texture region  51  makes the inner wall  121   a  of the metallic shell  11  form a rough surface, so that the sealing member  8  can attach onto the first texture region  51  efficiently. Therefore, the sealing member  8  does not overflow into the front portion of the receptacle cavity  112 , and the inner gap  211  can be sealed by the sealing member  8  properly. Hence, the first texture region  51  allows the sealing member  8  to attach onto the inner wall  121   a  of the shell body  121 , and the sealing member  8  can cover the inner gap  211  completely to provide a reliable waterproof performance. 
     Please refer to  FIGS. 5 to 7 . In this embodiment, the sealing member  8  is a waterproof glue block formed by drying and solidifying a liquid. Before the sealing member  8  is dried and set, the sealing member  8  fills into the inner gap  211  and the first glue recess  123 , penetrates into the channel, and fills the rear portion of the receptacle cavity  112 . Moreover, the sealing member also covers a gap between the rear lateral surface of the base portion  21  and the inner wall  121   a  of the shell body  121 . Accordingly, water moist cannot enter into the receptacle cavity  112  and the rear portion of the metallic shell  11  from the insertion opening  113  at the front portion of the metallic shell  11 . Therefore, when the electrical receptacle connector  100  is provided as a receptacle of an electronic device, water moist cannot enter into the electronic device and would not affect the operation of electronic components on a circuit board of the electronic device. 
     Please refer to  FIGS. 2 to 4 .  FIG. 4  illustrates a schematic configuration diagram of the receptacle terminals of the electrical receptacle connector shown in  FIG. 3 . The first receptacle terminals  31  comprise a plurality of first signal terminals  311 , at least one power terminal  312 , and at least one ground terminal  313 . From a front view of the first receptacle terminals  31 , the first receptacle terminals  31  comprise, from left to right, a ground terminal  313  (Gnd), a first pair of first signal terminals  3111  (TX 1 +−, differential signal terminals for high-speed signal transmission), a power terminal  312  (Power/VBUS), a first function detection terminal  3141  (CC 1 , a terminal for inserting orientation detection of the connector and for cable recognition), a second pair of first signal terminals  3112  (D+−, differential signal terminals for low-speed signal transmission), a first supplement terminal  3142  (SBU 1 , a terminal can be reserved for other purposes), another power terminal  312  (Power/VBUS), a third pair of first signal terminals  3113  (RX 2 +−, differential signal terminals for high-speed signal transmission), and another ground terminal  313  (Gnd). In this embodiment, twelve first receptacle terminals  31  are provided for transmitting USB 3.0 signals. In some embodiments, the rightmost ground terminal  313  (Gnd) (or the leftmost ground terminal  313  (Gnd)) or the first supplement terminal  3142  (SBU 1 ) can be further omitted. Therefore, the total number of the first receptacle terminals  31  can be reduced from twelve terminals to seven terminals. Furthermore, the ground terminal  313  (Gnd) may be replaced by a power terminal  312  (Power/VBUS) and provided for power transmission. In this embodiment, the width of the power terminal  312  (Power/VBUS) may be, but not limited to, equal to the width of the first signal terminal  311 . In some embodiments, the width of the power terminal  312  (Power/VBUS) may be greater than the width of the first signal terminal  311  and an electrical receptacle connector  100  having the power terminal  312  (Power/VBUS) can be provided for large current transmission. 
     Please refer to  FIGS. 2 to 4 . The first receptacle terminals  31  are held in the base portion  21  and the tongue portion  22  and formed as the upper-row terminals of the electrical receptacle connector  100 . In this embodiment, the first receptacle terminals  31  are assembled with the first portion. Each of the first receptacle terminals  31  comprises a flat contact portion  315 , a body portion  317 , and a tail portion  316 . For each of the first receptacle terminals  31 , the body portion  317  is held in the base portion  21  and the tongue portion  22 , the flat contact portion  315  is extending forward from the body portion  317  in the rear-to-front direction and partly exposed upon the first surface  221  of the tongue portion  22 , and the tail portion  316  is extending backward from the body portion  317  in the front-to-rear direction and protruding from the base portion  21 . The first signal terminals  311  are disposed on the first surface  221  and transmit first signals (namely, USB 3.0 signals). The tail portions  316  are protruding from the bottom surface of the base portion  21 . In addition, the tail portions  316  are bent horizontally to form flat legs, named legs manufactured by SMT (surface mounted technology), which can be mounted or soldered on the surface of a printed circuit board by using surface mount technology. Alternatively, the tail portions  316  may be extending downwardly to form vertical legs, named legs manufactured by through-hole technology, which can be inserted into holes drilled in a printed circuit board (PCB). 
     Please refer to  FIGS. 2 to 4 . The second receptacle terminals  41  comprise a plurality of second signal terminals  411 , at least one power terminal  412 , and at least one ground terminal  413 . From a front view of the second receptacle terminals  41 , the second receptacle terminals  41  comprise, from right to left, a ground terminal  413  (Gnd), a first pair of second signal terminals  4111  (TX 2 +−, differential signal terminals for high-speed signal transmission), a power terminal  412  (Power/VBUS), a second function detection terminal  4141  (CC 2 , a terminal for inserting orientation detection of the connector and for cable recognition), a second pair of second signal terminals  4112  (D+−, differential signal terminals for low-speed signal transmission), a second supplement terminal  4142  (SBU 2 , a terminal can be reserved for other purposes), another power terminals  412  (Power/VBUS), a third pair of second signal terminals  4113  (RX 1 +−, differential signal terminals for high-speed signal transmission), and another ground terminal  413  (Gnd). In this embodiment, twelve second receptacle terminals  41  are provided for transmitting USB 3.0 signals. In some embodiments, the rightmost ground terminal  413  (or the leftmost ground terminal  413 ) or the second supplement terminal  4142  (SBU 2 ) can be further omitted. Therefore, the total number of the second receptacle terminals  41  can be reduced from twelve terminals to seven terminals. Furthermore, the rightmost ground terminal  413  may be replaced by a power terminal  412  and provided for power transmission. In this embodiment, the width of the power terminal  412  (Power/VBUS) may be, but not limited to, equal to the width of the second signal terminal  411 . In some embodiments, the width of the power terminal  412  (Power/VBUS) may be greater than the width of the second signal terminal  411  and an electrical receptacle connector  100  having the power terminal  412  (Power/VBUS) can be provided for large current transmission. 
     Please refer to  FIGS. 2 to 4 . The second receptacle terminals  41  are held in the base portion  21  and the tongue portion  22  and formed as the lower-row terminals of the electrical receptacle connector  100 . In this embodiment, the second receptacle terminals  41  are assembled with the second portion. The first receptacle terminals  31  are substantially aligned parallel with the second receptacle terminals  41  and farer from the end portion of the tongue portion  22  (as compared with the second receptacle terminals  41 ). Each of the second receptacle terminals  41  comprises a flat contact portion  415 , a body portion  417 , and a tail portion  416 . For each of the second receptacle terminals  41 , the body portion  417  is held in the base portion  21  and the tongue portion  22 , the flat contact portion  415  is extending from the body portion  417  in the rear-to-front direction and partly exposed upon the second surface  222  of the tongue portion  22 , and the tail portion  416  is extending backward from the body portion  417  in the front-to-rear direction and protruding from the base portion  21 . The second signal terminals  411  are disposed at the second surface  222  and transmit second signals (i.e., USB 3.0 signals). In addition, the tail portions  416  are bent horizontally to form flat legs, named legs manufactured by SMT (surface mounted technology), which can be mounted or soldered on the surface of a printed circuit board by using surface mount technology. Alternatively, the tail portions  416  may be extending downwardly to form vertical legs, named legs manufactured by through-hole technology, which can be inserted into holes drilled in a printed circuit board (PCB). 
     Please refer to  FIGS. 2 to 4 . In this embodiment, the first receptacle terminals  31  and the second receptacle terminals  41  are disposed upon the first surface  221  and the second surface  222  of the tongue portion  22 , respectively, and pin-assignments of the first receptacle terminals  31  and the second receptacle terminals  41  are point-symmetrical with a central point of the receptacle cavity  112  as the symmetrical center. In other words, pin-assignments of the first receptacle terminals  31  and the second receptacle terminals  41  have 180-degree symmetrical design with respect to the central point of the receptacle cavity  112  as the symmetrical center. The dual or double orientation design enables an electrical plug connector to be inserted into the electrical receptacle connector  100  in either of two intuitive orientations, i.e., in either upside-up or upside-down directions. Here, point-symmetry means that after the first receptacle terminals  31  (or the second receptacle terminals  41 ), are rotated by 180 degrees with the symmetrical center as the rotating center, the first receptacle terminals  31  and the second receptacle terminals  41  are overlapped. That is, the rotated first receptacle terminals  31  are arranged at the position of the original second receptacle terminals  41 , and the rotated second receptacle terminals  41  are arranged at the position of the original first receptacle terminals  31 . In other words, the first receptacle terminals  31  and the second receptacle terminals  41  are arranged upside down, and the pin assignments of the flat contact portions  315  are left-right reversal with respect to that of the flat contact portions  415 . An electrical plug connector is inserted into the electrical receptacle connector  100  with a first orientation where the first surface  221  is facing up, for transmitting first signals. Conversely, the electrical plug connector is inserted into the electrical receptacle connector  100  with a second orientation where the first surface  221  is facing down, for transmitting second signals. Furthermore, the specification for transmitting the first signals is conformed to the specification for transmitting the second signals. Note that, the inserting orientation of the electrical plug connector is not limited by the electrical receptacle connector  100  according embodiments of the instant disclosure. 
     Please refer to  FIGS. 2 to 4 . In this embodiment, the position of the first receptacle terminals  31  corresponds to the position of the second receptacle terminals  41 . 
     Additionally, in some embodiments, the electrical receptacle connector  100  is devoid of the first receptacle terminals  31  (or the second receptacle terminals  41 ) when an electrical plug connector to be mated with the electrical receptacle connector  100  has upper and lower plug terminals. In the case that the first receptacle terminals  31  are omitted, the upper plug terminals or the lower plug terminals of the electrical plug connector are in contact with the second receptacle terminals  41  of the electrical receptacle connector  100  when the electrical plug connector is inserted into the electrical receptacle connector  100  with the dual orientations. Conversely, in the case that the second receptacle terminals  41  are omitted, the upper plug terminals or the lower plug terminals of the electrical plug connector are in contact with the first receptacle terminals  31  of the electrical receptacle connector  100  when the electrical plug connector is inserted into the electrical receptacle connector  100  with the dual orientations. 
     Please refer to  FIGS. 2 to 4 . In this embodiment, the tail portions  316 ,  416  are protruding from the base portion  21  and arranged separately. The tail portions  316 ,  416  may be arranged into two parallel rows. Alternatively, the tail portions  416  may be aligned into two rows and the first row of the tail portions  416  is aligned by an offset with respect to the second row of the tail portions  416 ; thus, the tail portions  316 ,  416  form three rows. 
     Please refer to  FIGS. 2 to 4 . In this embodiment, as viewed from the front of the receptacle terminals  31 ,  41 , the position of the first receptacle terminals  31  corresponds to the position of the second receptacle terminals  41 . In other words, the positions of the flat contact portions  315  are respectively aligned with the positions of the flat contact portions  415 , but embodiments are not limited thereto. In some embodiments, the first receptacle terminals  31  may be aligned by an offset with respect to the second receptacle terminals  41 . That is, the flat contact portions  315  are aligned by an offset with respect to the flat contact portions  415 . Accordingly, because of the offset alignment of the flat contact portions  315 ,  415 , the crosstalk between the first receptacle terminals  31  and the second receptacle terminals  41  can be reduced during signal transmission. It is understood that, when the receptacle terminals  31 ,  41  of the electrical receptacle connector  100  have the offset alignment, plug terminals of an electrical plug connector to be mated with the electrical receptacle connector  100  would also have the offset alignment. Hence, the plug terminals of the electrical plug connector can be in contact with the receptacle terminals  31 ,  41  of the electrical receptacle connector  100  for power or signal transmission. 
     In the foregoing embodiments, the receptacle terminals  31 ,  41  are provided for transmitting USB 3.0 signals, but embodiments are not limited thereto. In some embodiments, for the first receptacle terminals  31  in accordance with transmission of USB 2.0 signals, the first pair of the first signal terminals  3111  (TX 1 +−) and the third pair of the first signal terminals  3113  (RX 2 +−) are omitted, and the second pair of the first signal terminals  3112  (D+−) and the power terminals  312  (Power/VBUS) are retained. While for the second receptacle terminals  41  in accordance with transmission of USB 2.0 signals, the first pair of the second signal terminals  4111  (TX 2 +−) and the third pair of the second signal terminals  4113  (RX 1 +−) are omitted, and the second pair of the second signal terminals  4112  (D+−) and the power terminals  412  (Power/VBUS) are retained. 
     Please refer to  FIGS. 2 and 3 . In some embodiment, the electrical receptacle connector  100  further comprises a shielding plate  7 . The shielding plate  7  is held in the insulated housing  2 . The shielding plate  7  comprises a plate body  71  and a plurality of contact parts  72 . The plate body  71  is between the flat contact portions  315  of the first receptacle terminals  31  and the flat contact portions  415  of the second receptacle terminals  41 . In other words, the plate body  71  is formed in the base portion  21  and the tongue portion  22  and between the flat contact portion  315  and the flat contact portions  415 . The contact parts  72  may be extending downwardly from two sides of the plate body  71  and out of the bottom of the base portion  21 , and the contact parts  72  are in contact with contacts of the circuit board. Alternatively, the contact parts  72  may be extending backwardly from two sides of the plate body  71  and out of the rear portion of the base portion  21 , and the contact parts  72  are in contact with the metallic shell  11 . Accordingly, the crosstalk interference can be reduced by the shielding of the shielding plate  7  when the flat contact portions  315 ,  415  transmit signals. Furthermore, the structural strength of the tongue portion  22  can be improved by the assembly of the shielding plate  7 . In addition, the contact parts  72  of the shielding plate  7  are extending downwardly to form vertical legs; that is, the contact parts  72  are exposed from the base portion  21  and in contact with the circuit board. Moreover, the shielding plate  7  comprises a plurality of hooks  73 . The hooks  73  are extending outward from two sides of the plate body  71 . When an electrical plug connector is mated with the electrical receptacle connector  100 , elastic pieces at two sides of an insulated housing of the electrical plug connector are engaged with the hooks  73 , and the elastic pieces would not wear against the tongue portion  22  of the electrical receptacle connector  100 . Hence, the shielding plate  7  can be in contact with the metallic shell of the plug connector for conduction and grounding. 
     Furthermore, the electrical receptacle connector  100  further comprises a plurality of conductive sheets. The conductive sheets are metallic elongated sheets, an upper conductive sheet is above the base portion  21 , and a lower conductive sheet is below the base portion  21 . When an electrical plug connector is mated with the electrical receptacle connector  100 , the front end of the metallic shell of the electrical plug connector is in contact with the conductive sheets, so that the metallic shell of the electrical plug connector and the metallic shell  11  of the electrical receptacle connector  100  can be connected with each other. Accordingly, the connection between the shells of the connectors can be grounded and the electromagnetic interference (EMI) during the signal transmission can be reduced by the conductive sheets. 
     Please refer to  FIGS. 8 and 9 , illustrating an electrical receptacle connector  100  of a second embodiment of the instant disclosure.  FIG. 8  illustrates an exploded view of the electrical receptacle connector.  FIG. 9  illustrates an enlarged lateral view of the first texture region of the electrical receptacle connector. In this embodiment, the metallic shell  11  is further enclosed by an enveloping shell  6  to form a second glue recess  61 . In this embodiment, the electrical receptacle connector  100  further comprises an enveloping shell  6 . The enveloping shell  6  is a replacement for the case  124  of the first embodiment. In this embodiment, the enveloping shell  6  is a plastic shell. The enveloping shell  6  circularly encloses the shell body  121 . An end portion  611  of the enveloping shell  6  corresponding to the rear end  116  of the shell body  121  is protruding from the lateral surface of the base portion  21  to form a second glue recess  61 . The sealing member  8  can be filled into the second glue recess  61 , and the sealing member  8  penetrates into the inner gap  211  and fills the first texture region  51 . 
     Please refer to  FIG. 10 , illustrating another enlarged lateral view of the electrical receptacle connector having second texture region. In one embodiment, the shell body  121  further comprises a second texture region  52  annularly formed on an outer wall  121   b  of the shell body  121 . An outer gap  63  is formed between an inner wall of the enveloping shell  6  corresponding to the rear end  116  of the shell body  121  and the outer wall  121   b  of the shell body  121 . The second texture region  52  may be patterns formed by pressing techniques and may be aligned equidistantly or unequidistantly. The second texture region  52  may be aligned parallel (not overlapped) or nonparallel (overlapped), and the shape of the second texture region  52  may be rectangle, triangle, etc. It is understood that, the width of the second texture region  52  and the roughness of the pattern on the second texture region  52  can be altered according to glues with different viscosities. The second texture region  52  makes the outer wall  121   b  of the shell body  121  form a rough surface, so that the sealing member  8  can attach onto the second texture region  52  efficiently. Therefore, the sealing member  8  does not overflow into the front portion of the receptacle cavity  112 , and the outer gap  63  can be sealed by the sealing member  8  properly. Hence, the second texture region  52  allows the sealing member  8  to attach onto the outer wall  121   b  of the shell body  121 , and the sealing member  8  can cover the outer gap  63  completely to provide a reliable waterproof performance. 
     Please refer to  FIGS. 11 and 12 , illustrating an electrical receptacle connector  100  of a third embodiment of the instant disclosure.  FIG. 11  illustrates an exploded view of an electrical receptacle connector of the third embodiment.  FIG. 12  illustrates an enlarged view of the electrical receptacle connector of the third embodiment. In this embodiment, the base portion  21  is located at an end portion  1211  of the shell body  121 , and the rear end  116  of the shell body  121  is protruding from a lateral surface of the base portion  21  to form a first glue recess  123 . The enveloping shell  6  circularly encloses the shell body  121 . An end portion  611  of the enveloping shell  6  corresponding to the rear end  116  of the shell body  121  is protruding from the lateral surface of the base portion  21  to form a second glue recess  61 , wherein the second glue recess  61  comprises the first glue recess  123 . That is, the region of the second glue recess  61  for receiving the sealing member  8  contains the first glue recess  123 . 
     When the sealing member  8  in liquid state fills into the second glue recess  61 , the sealing member  8  penetrates into the insulated housing  2  and is distributed within the inner gap  211 , so that the inner gap  211  is completely sealed by the sealing member  8 . In addition, the outer gap  63  between the outer wall  121   b  of the shell body  121  and the inner wall of the enveloping shell  6  is completely filled by the sealing member  8 . Therefore, the electrical receptacle connector  100  can provide a reliable waterproof performance. 
     As above, the first texture region makes the inner wall of the metallic shell form a rough surface, so that the sealing member can attach onto the first texture region efficiently. Therefore, the sealing member does not overflow into the front portion of the receptacle cavity, and the inner gap can be sealed by the sealing member properly. Hence, the first texture region allows the sealing member to attach onto the inner wall of the shell body, and the sealing member can cover the inner gap completely to provide a reliable waterproof performance. Furthermore, the second texture region makes the outer wall of the shell body form a rough surface, so that the sealing member can attach onto the second texture region efficiently. Therefore, the sealing member does not overflow into the front portion of the receptacle cavity, and the outer gap can be sealed by the sealing member properly. Hence, the second texture region allows the sealing member to attach onto the outer wall of the shell body, and the sealing member can cover the outer gap completely to provide a reliable waterproof performance. 
     Furthermore, the first receptacle terminals and the second receptacle terminals are arranged upside down, and the pin-assignment of the flat contact portions of the first receptacle terminals is left-right reversal with respect to that of the flat contact portions of the second receptacle terminals. Accordingly, the electrical receptacle connector can have a 180-degree symmetrical, dual or double orientation design and pin assignments which enables the electrical receptacle connector to be mated with a corresponding plug connector in either of two intuitive orientations, i.e. in either upside-up or upside-down directions. Therefore, when an electrical plug connector is inserted into the electrical receptacle connector with a first orientation, the flat contact portions of the first receptacle terminals are in contact with upper-row plug terminals of the electrical plug connector. Conversely, when the electrical plug connector is inserted into the electrical receptacle connector with a second orientation, the flat contact portions of the second receptacle terminals are in contact with the upper-row plug terminals of the electrical plug connector. Note that, the inserting orientation of the electrical plug connector is not limited by the electrical receptacle connector of the instant disclosure. 
     While the instant disclosure has been described by the way of example and in terms of the preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.