Patent Publication Number: US-2009218120-A1

Title: Printed circuit board, electronic device and connector

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2008-050574, filed Feb. 29, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     One embodiment of the present invention relates to a printed circuit board comprising a connector which forms a connection section along with a mating connector, an electronic device, and a connector. 
     2. Description of the Related Art 
     For example, Jpn. Pat. Appln. KOKAI Publication No. 2001-155829 discloses a card edge connector which prevents components from being damaged when a card-edge printed board is inserted or extracted. The card edge connector is fixed on a printed board provided independently from the card-edge printed board. The card edge connector comprises a fixed-side housing including a first contact pin for electrically connecting to the printed board, and a rotating-side connector housing rotatably supported by the fixed-side housing. The rotating-side housing includes a second contact pin electrically connected to a pad portion of the printed board and an abutting portion against which the card-edge printed board is made to abut when inserted. Further, the card-edge printed board is inserted between the fixed-side housing and the rotating-side housing. 
     When a card-edge printed board is inserted into the card edge connector, an end portion of the card-edge printed board is made to abut the abutting portion, and the rotating-side housing rotates toward the fixed-side housing. Thereby, the card-edge printed board is sandwiched between the first contact pin of the fixed-side housing and the second contact pin of the rotating-side housing. Thus, electrical conduction between a card-edge printed board and a printed board provided independently from the card-edge printed board is achieved. 
     The above-described card edge connector is automatically mounted on the surface of the printed board by a mounter, for example, by means of a surface mount technology (SMT). On the other hand, there is also a connector in which a printed board is interposed between both sides. This kind of connector includes a housing, a terminal provided inside the housing and connected to a pad portion of the printed board, and a supporting section formed in the housing to support the printed board by interposing the printed board in between. When such an interposed-type connector is mounted, the connector is inserted in a direction parallel to the board such that the printed board is interposed inside the supporting section. 
     When the above-described interposed-type connector is fixed on the printed board, the connector is inserted into the printed board, on the surface of the pad section of which solder paste is applied. In this case, there is a possibility that a terminal rubs against the solder paste on the surface of the pad section. Thereby, a short may be caused between adjacent pad sections, solder balls may be formed, or solder joints may not be formed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
         FIG. 1  is an exemplary perspective view showing a portable computer according to a first embodiment of the present invention. 
         FIG. 2  is an exemplary perspective view showing a printed circuit board of the portable computer shown in  FIG. 1 . 
         FIG. 3  is an exemplary exploded perspective view showing peripheral structures of a connector of the printed circuit board shown in  FIG. 2 . 
         FIG. 4  is an exemplary exploded perspective view showing an inner structure of the connector shown in  FIG. 3 . 
         FIG. 5  is an exemplary longitudinal cross-sectional view of the connector and a printed wiring board shown in  FIG. 3 . 
         FIG. 6  is an exemplary cross-sectional view of a state in which the printed wiring board shown in  FIG. 5  is inserted into an insertion section of the connector. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, a printed circuit board includes a printed wiring board and a connector. The connector includes a housing, a lead received inside the housing, an insertion section which is provided in the housing and to which the printed wiring board is inserted, and a rotating mechanism. The rotating mechanism moves the lead to a first position in which the lead is separated from the printed wiring board by abutting the lead and moves the lead to a second position in which the lead is connected to the pad of the printed wiring board via the solder by rotating and separating from the lead when the printed wiring board is inserted into the insertion section. 
     Hereinafter, the first embodiment of an electronic device will be described with reference to  FIGS. 1-6 . As shown in  FIG. 1 , a portable computer  11 , which is an example of the electronic device, comprises a main body unit  12 , a display unit  13 , and a hinge section  14  provided between the main body unit  12  and the display unit  13 . The hinge section  14  supports the display unit  13  and is capable of rotating the display unit  13  with respect to the main body unit  12 . The display unit  13  includes a liquid crystal display  15  and a latch  16 . 
     The main body unit  12  includes a casing  21  formed of synthetic resin, a main substrate  22  provided inside the casing  21 , a printed circuit board  23  provided independently from the main substrate  22 , and a keyboard  24  and a touchpad  25  provided on the casing  21 . On the main substrate  22 , a central processing unit (CPU) and various random access memories (RAMs) and read-only memories (ROMs) are mounted. 
     The printed circuit board  23  is an example of a solid state drive (SSD) or a flash memory drive. The printed circuit board  23  is a drive device which uses a flash memory as a memory device, and uses a connection interface protocol (ATA protocol) common to the hard disk drive (HDD). 
     As shown in  FIG. 2 , the printed circuit board  23  includes a printed wiring board  31  and a plurality of flash memories  32  which are circuit components mounted on the printed wiring board  31 , a controller  33  mounted on the printed wiring board  31 , and a connector  34  fixed to the printed wiring board  31 . The flash memories  32  are mounted on both sides of the printed wiring board  31  of the printed circuit board  23 . The printed circuit board  23  is provided inside a metal housing, not shown. The size of the metal housing may be the same as the size of a 1.8-inch HDD, for example. The printed circuit board  23  is plugged compatible with a 1.8-inch HDD. 
     The printed wiring board  31  is a copper-clad laminate formed by stacking a plurality of copper wiring layers. As shown in  FIGS. 2-4 , the printed wiring board  31  includes a first surface  31 A, a second surface  31 B opposite to the first surface  31 A, and pads  35  provided on at least one of the first surface  31 A and the second surface  31 B. The printed wiring board  31  includes an approximately square notch  36 , an edge portion  37  which defines the periphery of the notch  36 , a pair of first portions  38  each provided at a recess  41  of the notch  36 , a pair of second portions  39  each provided at a subterminal portion  42  opposite to the recess  41  of the notch  36 , and fixing holes  40  provided in the respective corner sections. In the present embodiment, a plurality of pads  35  are provided adjacent to the notch  36  on the first surface  31 A. Each of the first sections  38  projects in the form of a fragment from the corner of the recess  41  of the notch  36 . The first sections  38  are inserted into a pair of insertion sections  49  of the connector  34 , which will be described below. 
     The second sections  39  are formed of subterminal sections  42 , i.e., a pair of corner sections which are introductory parts of the notch  36 . The second sections  39  are inserted into a pair of guide sections  50  of the connector  34 , which will be described below. As shown in  FIG. 3 , the second sections  39  are provided closer to the connector  34  than the first sections  38 . On upper surfaces of the pads  35 , paste-form solder cream  43  is printed or applied. 
     The connector  34  is a so-called plug-in (straddle) connector. The connector  34  is not mounted on a surface, but is mounted astride lateral portions of the printed wiring board  31 , i.e., astride the first surface  31 A and the second surface  31 B. The connector  34  includes a box-like housing  46 , a plurality of leads  47  received inside the housing  46 , a rotating mechanism  48  for adjusting the positions of the leads  47 , and insertion sections  49  and the guide sections  50  formed in the housing  46 . The leads  47  have connecting portions  47 A at the tips, which are electrically connected to the pads  35  via the solder cream. The leads  47  are formed of phosphor bronze or brass. 
     The number of leads  47  may be  16 , for example, and are compatible with Micro-SATA. This number of the leads  47  is an example and may be  22  or  26 . In  FIGS. 3 and 4 , the number of the shown leads  47  is only  4 . When the number of the leads  47  is set to  22 , it is preferable to make the size of the metal housing same as the size of a 2.5-inch HDD and secure compatibility therebetween. Similarly, when the number of the leads  47  is set to  26 , it is preferable to make the size of the metal housing same as the size of a 3.5-inch HDD and secure compatibility therebetween. 
     The housing  46  is formed of synthetic resin such as liquid crystal polymer (LCP) and polyphenylenesulfide (PPS). 
     The pair of guide sections  50  is formed at both end sections of the housing  46  in a width direction. Each of the guide sections  50  is in the form of a groove. The width of the groove is the same as or slightly greater than the thickness of the printed wiring board  31 . The printed wiring board  31  can be supported inside the groove-like guide sections  50  such that the printed wiring board  31  is interposed in between. The second portions  39  of the printed wiring board  31  are inserted into the guide sections  50 . 
     The pair of insertion sections  49  is provided independently from the guide sections  50 . Each of the insertion sections  49  is in the form of a groove and is provided inside each of the guide sections  50  at each of the both end sections of the housing  46  in the width direction. The width of the groove of each of the insertion sections  49  is the same as or slightly greater than the thickness of the printed wiring board  31 . The first sections  38  of the printed wiring board  31  are inserted into the insertion sections  49 . 
     The rotating mechanism  48  includes a rotating member  53  received inside the housing  46  and a spring  54  which urges the rotating member  53 . The rotating member  53  includes an axis  53 A provided rotatably inside the housing  46 , a first lever  53 B extending from the axis  53 A in a radial direction of the axis  53 A, and a pair of second levers  53 C extending from the axis  53 A in a radial direction of the axis  53 A, which is different from the direction of the first lever  53 B. The axis  53 A is in the form of a column. The housing  46  includes an axis receiver, not shown, capable of rotatably supporting the axis  53 A. The axis receiver is formed inside the housing  46  as a recess which opens downward in a shape complementary to the axis  53 A. The rotating member  53  is mounted inside the housing  46  by engaging the axis  53 A in the axis receiver from below the housing  46 . Further, the rotating member  53  may be detached from the housing  46  by releasing the axis  53 A from the axis receiver. 
     The first lever  53 B is in the form of a flat plate and extends toward the leads  47 . The number of the first levers  53 B provided is  16  in total, such that the first levers  53 B correspond to the leads  47  one by one. The first levers  53 B abut the leads  47 , and thereby the leads  47  can be moved to a first position P 1 . The second levers  53 C are arranged inside the housing  46  in the vicinity of the insertion section  49 . The spring  54  is attached inside a cylindrical mounting section  55  formed in the housing  46 . The spring  54  is arranged in a compressed state between the second lever  53 C and an inside of the housing  46 . Therefore, the spring  54  urges the rotating member  53  in a clockwise direction in  FIG. 5 . The spring  54  holds the first lever  53 B against the leads  47  and urges the second lever  53 C to move the leads  47  to the first position P 1  in advance. 
     Next, operations of the rotating mechanism  48  of the connector  34  according to the present embodiment will be described with reference to  FIGS. 5 and 6 . As shown in  FIG. 5 , the printed wiring board  31  is brought near the connector  34 . In this state, the lead  47  is supported by the spring  54  in the first position P 1  in which the leads  47  is separated from the printed wiring board  31 . That is, the lead  47  is in an upper position than the position of a standard line S indicating a state in which no power is applied by the rotating member  53  of the rotating mechanism  48 , as shown in  FIG. 5 . 
     Before the first section  38  of the printed wiring board  31  is inserted into the insertion section  49  of the connector  34 , the second section  39  of the printed wiring board  31  is inserted into the guide section  50  of the connector  34 . Thereby, the general position of the connector  34  is determined with respect to the printed wiring board  31 . Then, as shown in  FIG. 6 , the second section  39  of the printed wiring board  31  is inserted into the insertion section  49  of the connector  34 . In this state, the second section  39  abuts the second lever  53 C of the rotating member  53 , and is inserted inside the insertion section  49  against the urging force of the spring  54 . Thereby, the rotating member  53  of the rotating mechanism  48  is made to rotate and the first lever  53 B is separated from the lead  47 . Thus, the lead  47  is moved to a second position P 2  in which the lead  47  is in contact with the pad  35  of the printed wiring board  31 . The lead  47  is brought into a state of being connected with the pad  35  via the solder cream  43 . 
     The insertion of the connector  34  to the printed wiring board  31  is performed as part of manual post processing. In this case, it is necessary that a person intervenes in an SMT line. However, this can be automated by introducing a robot, for example. The printed circuit board  23  is sent to a reflow furnace in a state where the connector  34  is inserted into the printed wiring board  31 , and the solder cream  43  is melt. By cooling the printed circuit board  23 , solder connection of the printed circuit board  23  is completed. 
     When the connector  34  is detached from the printed wiring board  31  to repair the connector  34 , solder joints between the leads  47  and the pads  35  are heated by spot air. After the solder joints are melted, the connector  34  is detached from the printed wiring board  31 . At this time, the leads  47  are removed from the second position P 2  to the first position P 1  by the rotating mechanism  48 . Therefore, the leads  47  are not made into contact with the printed wiring board  31 , and the problem that the melted solder is rubbed over the printed wiring board  31  does not occur. 
     According to the present embodiment, a printed circuit board  23  comprises a printed wiring board  31  including a first surface  31 A, a second surface  31 B opposite to the first surface  31 A, pads  35  provided on at least one of the first surface  31 A and the second surface  31 B, and solder  43  applied on the pads  35 , and a connector  34  attached to the printed wiring board  31  astride the first surface  31 A and the second surface  31 B. The connector  34  includes a housing  46  and leads  47  received inside the housing  46 , an insertion section  49  to which the printed wiring board  31  is inserted, and a rotating mechanism  48  which moves the leads  47  to a first position P 1  in which the leads  47  are separated from the printed wiring board  31  and moves the leads  47  to a second position P 2  in which the leads  47  are connected to the pads  35  of the printed wiring board  31  via solder  43  by rotating and separating from the leads  47  when the printed wiring board  31  is inserted into the insertion section  49 . 
     With the aforementioned configuration, when the connector  34  is attached to the printed wiring board  31 , the leads  47  can be maintained in the first position P 1  in which the leads  47  are separated from the printed wiring board  31 . Thereby, when the connector  34  is attached to the printed wiring board  31 , the leads  47  do not rub over the surface of the printed wiring board  31 . Therefore, it is possible to prevent the solder cream  43  applied on the pads  35  of the printed wiring board  31  from being removed. It is therefore possible to prevent such problems that the solder cream  43  is applied in unintended areas and a short occurs between adjacent pads  35 , solder balls are formed from the removed solder cream  43 , and solder joints are not formed. 
     Further, since the leads  47  abut the printed wiring board  31  when the connector  34  is mounted, it is possible to prevent the leads  47  from being bent mistakenly. Further, since the connector  34  is configured to be arranged astride the first surface  31 A and the second surface  31 B, mounting space can be secured on both sides of the printed wiring board  31  within the height of the connector  34 . Thereby, circuit components such as flash memories  32  can be mounted with high density on both sides of the first surface  31 A and the second surface  31 B of the printed wiring board  31 . 
     With the structure of providing an insertion section  49 , the connector  34  can be arranged on a plane to which the printed wiring board  31  extends. Thereby, concentration of stress on solder joints between the connector  34  and the printed wiring board  31  can be prevented. 
     In this case, the rotating mechanism  48  comprises a rotating member  53  including an axis  53 A rotatably mounted inside the housing  46 , a first lever  53 B which extends from the axis  53 A in the radial direction of the axis  53 A and abuts the leads  47  to move the leads  47  to the first position P 1 , and a second lever  53 C which extends from the axis  53 A in the radial direction of the axis section  53 A and arranged in the vicinity of the insertion section  49 , and a spring  54  which is arranged between the second lever  53 C and the inside of the housing  46  in a compressed state and urges the second lever  53 C such that the first lever  53 B abuts the leads  47  and the leads  47  are moved to the first position P 1  in advance. Since the printed wiring board  31  inserted into the insertion section  49  abuts the second lever  53 C, the rotating member  53  rotates, and the first lever  53 B is separated from the leads  47  and moves the leads  47  to the second position P 2 . 
     According to the aforementioned configuration, it is possible to provide a connector  34  and a printed wiring board  31  capable of evacuating the leads  47  to the first position P 1  separated from the printed wiring board  31  with a simple configuration utilizing the urging power of the spring  54 . On the other hand, since the urging power of the spring  54  is released by inserting the printed wiring board  31  to the insertion section  49 , the leads  47  can be moved to the second position P 2  after inserting the printed wiring board  31  to the insertion section  49 . Thereby, the leads  47  can be removed to the first position P 1  at the time of mounting during which the cream solder  43  may be rubbed. After the mounting is finished, the leads  47  can be soft landed on the printed wiring board  31 , such that the leads  47  are maintained in the second position P 2  in which the leads  47  are in contact with the printed wiring board  31 . Therefore, even by providing the rotating mechanism  48 , no problems occur in solder joints. 
     In this case, the housing  46  includes a guide  50  provided independently from the insertion section  49 . The guide  50  is formed like a groove, and configured to support the printed wiring board  31  such that the printed wiring board  31  is interposed in between inside the groove. With this configuration, the printed wiring board  31  can be supported by the guide  50  as well as the insertion section  49  such that the printed wiring board  31  is interposed in between, and the connector  34  can be solidly fixed to the printed wiring board  31 . Further, when a mating connector is connected or disconnected in a state where the connector  34  is mounted on an electronic device, power is applied to the connector  34 . In such a case, the power can be prevented from being applied to the connector  34  via the guide  50  such that the power is applied to the printed wiring board  23 . Thereby, it is possible to prevent concentration of stress on solder joints and occurrence of cracks in solder joints. 
     In this case, the printed wiring board  31  includes a first section  38  inserted into the insertion section  49  and a second section  39  provided in a position nearer to the connector  34  than the first section  38  and interposed by the guide section  50 . 
     According to the above-described configuration, since the second section  39  is provided in a position nearer to the connector  34  than the first section  38 , the printed wiring board  31  can be inserted into the guide section  50  before the printed wiring board  31  is inserted into the insertion section  49 . Thereby, the first section  38  can be inserted into the insertion section  49  in a state where the position of the connector  34  is determined by the guide section  50  in advance, and the mounting position of the connector  34  does not deviate from the correct position. Therefore, it is possible to prevent the problem that soldered connection is made in a state where the leads  47  are removed to the first position P 1 . 
     In this case, the printed wiring board  31  includes a notch  36  for attaching a connector  34 , and the first section  38  is provided in a recess  41  of the notch  36 . With this configuration, it is not necessary to provide the first section  38  inserted into the insertion section  49  in a protruding form, and it is possible to prevent problems occurred in forming the first section  38  in a protruding form, i.e., the problems that the first section  38  is made sharp and hazardous and that the first section  38  is made frangible. 
     In this case, the second section  39  is provided in a subterminal section  42  opposite to the recess  41  of the notch  36 . According to this configuration, the second section  39  provided nearer to the connector  34  than the first section  38  can be formed on the printed wiring board  31  with a simple configuration. 
     In this case, a pair of guides  50  is provided on both terminals of the housing  46  in the width direction. According to this structure, the position of the connector  34  can be determined at both terminal sections of the housing  46  in the width direction, and the accuracy of attaching the connector  34  to the printed wiring board  31  can be improved. 
     The electronic device of the present invention is not limited to a portable computer. The present invention can be implemented with respect to other electronic devices such as a portable digital assistant. Various modifications may be made to the electronic device without departing from the spirit or scope of the general inventive concept. 
     While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.