Abstract:
The present invention is adapted to a memory system that includes: a motherboard and a module board, wherein: the motherboard comprises a module socket mounted on the motherboard; and a plurality of pins two-dimensionally arranged on the module socket, and vertically erected with respect to the motherboard: and the module board comprises a plurality of device chips installed on the module board; and a contact portion mounted on the module board, and including a plurality of through holes two-dimensionally arranged thereon, the contact portion being electrically connected to the device chips: wherein each of the pins is inserted into each of the through holes to connect electrically to the contact portion.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a technique for installing memory modules each having a plurality of memories mounted thereon to a module socket. 
         [0003]    2. Description of Related Art 
         [0004]    Conventionally, it is often performed in a memory system using a large number of memories such as a DRAM (Dynamic Random Access Memory) that a plurality of memories are mounted on the module board of a memory module and the memory module is then installed in a module socket mounted on a motherboard. In addition, for the form of the module socket, a typical form is one in which a single memory module is vertically mounted on a motherboard as disclosed in JP2009-294864A and JP2010-027137A. 
         [0005]    Now, in these years, in order to reduce the size and thickness of desktop personal computers, a trend has developed in which the motherboard is a small-sized motherboard such as MicroATX or Mini-ITX, and this trend is becoming the mainstream of memory systems as well. 
         [0006]    However, in the form of typical modern module sockets, in the case that the number of memory modules to be installed is increased, the number of module sockets is increased correspondingly, so that the motherboard needs the area for module sockets. This goes against the trend toward a reduction in the size of the motherboard. 
         [0007]    In addition, in the case of increasing the number of memory modules to be installed, the number of module sockets is increased correspondingly as discussed above. In this case, as regards the positions at which module sockets are placed, limitations are placed on the thickness of the module socket or on the wires or the like around the module socket. For this reason, a memory module installed in a module socket located at a position more apart from a CPU has a longer bus length to the CPU, and this bus length becomes a bottleneck against an increase in the speed of the memory system. 
         [0008]    As described above, in the memory system, the problem to be solved is to install an increased number of memory modules without increasing the area of the motherboard. In addition, in the memory system, another problem to be solved is to install an increased number of memory modules without increasing the bus length between the CPU and the memory module. 
       SUMMARY 
       [0009]    In one embodiment, there is provided a memory system that includes: a motherboard and a module board, wherein: the motherboard comprises a module socket mounted on the motherboard; and a plurality of pins two-dimensionally arranged on the module socket, and vertically erected with respect to the motherboard: and the module board comprises a plurality of device chips installed on the module board; and a contact portion mounted on the module board, and including a plurality of through holes two-dimensionally arranged thereon, the contact portion being electrically connected to the device chips: wherein each of the pins is inserted into each of the through holes to connect electrically to the contact portion. 
         [0010]    In another embodiment, there is provided a memory module that includes a module board; a plurality of device chips installed on the module board; and a contact portion mounted on the module board, and including a plurality of through holes two-dimensionally arranged thereon, the contact portion being electrically connected to the device chips. 
         [0011]    In further another embodiment, there is provided a module socket that includes a motherboard; and a plurality of pins two-dimensionally arranged on the motherboard, and vertically erected with respect to the motherboard. 
         [0012]    In accordance with the memory system according to the present invention, a plurality of pins, that are two-dimensionally arranged on the module socket, are vertically erected with respect to the motherboard, and a plurality of through holes are arranged on the module board, into which the plurality of pins are inserted. 
         [0013]    Thus, it is possible to install the memory module to the module socket so that the memory module is horizontally installed with respect to the motherboard. In the case of increasing the number of memory modules to be installed, memory modules are stacked on a module socket for insertion. 
         [0014]    Accordingly, because a single module socket is used to install a plurality of memory modules thereto, there is obtained the effect in which it is possible to increase the number of memory modules to be installed without increasing the area of a motherboard. 
         [0015]    In addition, because a single module socket is used to install a plurality of memory modules thereto, no limitations are placed on the thickness of the module socket or the wires or the like around the module socket. Thus, the degree of freedom to arrange a module socket is increased, and it is also possible to mount a module socket at a position which is the shortest distance from a CPU. Accordingly, there is obtained the effect in which it is possible to increase the number of memory modules to be installed without increasing the bus length between a CPU and a memory module. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a perspective view depicting an exemplary configuration of a memory system according to an embodiment of the present invention; 
           [0018]      FIG. 2  is a top view depicting an exemplary configuration of a memory module shown in  FIG. 1 ; 
           [0019]      FIG. 3  is a cross sectional view depicting an exemplary configuration of a module socket shown in  FIG. 1 ; 
           [0020]      FIG. 4  is a diagram illustrative of an exemplary method of contacting a pin shown in  FIG. 1  with a through hole; 
           [0021]      FIG. 5  is a diagram illustrative of an exemplary method of contacting a pin shown in  FIG. 1  with a through hole; 
           [0022]      FIG. 6  is a diagram illustrative of an exemplary method of contacting a pin shown in  FIG. 1  with a through hole; 
           [0023]      FIG. 7  is a diagram illustrative of an exemplary method of contacting a pin shown in  FIG. 1  with a through hole; 
           [0024]      FIG. 8  is a diagram illustrative of an exemplary method of applying a lateral pressure to a module board shown in  FIG. 1 ; 
           [0025]      FIG. 9  is a diagram illustrative of an exemplary relationship between the positions of the module socket shown in  FIG. 1  and a CPU; 
           [0026]      FIG. 10  is a diagram illustrative of an exemplary relationship between the positions of the module socket shown in  FIG. 1  and a CPU; 
           [0027]      FIG. 11A  is a diagram illustrative of an exemplary effect of a typical memory system; 
           [0028]      FIG. 11B  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 ; 
           [0029]      FIG. 11C  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 ; 
           [0030]      FIG. 12A  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 ; 
           [0031]      FIG. 12B  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 ; 
           [0032]      FIG. 13A  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 ; and 
           [0033]      FIG. 13B  is a diagram illustrative of an exemplary effect of the memory system shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    The invention will be now described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes. 
       1. Configuration of Memory System 
       [0035]    First, the configuration of a memory system according to this embodiment will be described with reference to  FIG. 1 . In addition,  FIG. 1  extracts and shows only the configuration around memory module  10  and module socket  20 . 
         [0036]    As shown in  FIG. 1 , the memory system according to this embodiment includes memory module  10  having a plurality of memories  11 , serving as a device chip, installed on module board  12 , and module socket  20  mounted on motherboard  30  for installing memory module  10  thereto. 
         [0037]    Here, module socket  20  is a pin socket having a plurality of pins  21  two-dimensionally arranged, and which is mounted in such a way that each of the plurality of pins  21  is vertically erected with respect to motherboard  30  and is connected electrically to a wire on motherboard  30 . In addition, the term “vertical” includes those pins considered to be substantially vertical, not limited to being completely vertical. 
         [0038]    In addition, memory module  10  includes contact portion  13  having a plurality of through holes  14  two-dimensionally arranged on module board  12  as corresponding to a plurality of pins  21 , and corresponding pin  21  is inserted into each of the plurality of through holes  14  and is connected electrically to a wire on module board  12 . Therefore, each of the plurality of pins  21  is connected electrically to contact portion  13 , and contact portion  13  is connected electrically to contact memory  11 . Thus, power or signals are supplied to memory  11  from pin  21  via through hole  14 . In addition, because each through hole  14  is used for an electrode as discussed above, the inner wall is plated or coated with a conductive material, and has a diameter that is greater than the diameter of pin  21  so as to allow pin  21  to be inserted. 
         [0039]    The memory system according to this embodiment is configured as described above, so that it is possible to install memory module  10  to module socket  20  horizontally with respect to motherboard  30 . In addition, in the case where a plurality of memory modules  10  are installed to module socket  20 , it is sufficient that memory modules  10  are stacked and that pins  21  of module socket  20  are inserted into through holes  14  in memory module  10 . 
         [0040]    In this embodiment, as described above with reference to  FIG. 1 , the effect in which it is possible to install a plurality of memory modules  10  horizontally to motherboard  30  will be described in detail below in 7-1. 
       2. Configuration of Memory Module  10   
       [0041]    Next, the detailed configuration of memory module  10  will be described with reference to  FIG. 2 . 
         [0042]    As shown in  FIG. 2 , on module board  12 , contact portion  13  is arranged at almost the center part, and a plurality of memories  11  are installed around contact portion  13  so as to surround contact portion  13 . In addition, module fixing hole  15  is arranged on module board  12  for fixing memory module  10  to module socket  20 . 
         [0043]    In this embodiment, as described with reference to  FIG. 2  above, the effect in which it is possible to install a plurality of memories  11  around contact portion  13  at the center of module board  12  will be described in detail below in 7-2. 
       3. Configuration of Module Socket  20   
       [0044]    Next, the detailed configuration of module socket  20  will be described with reference to  FIG. 3 . 
         [0045]    As shown in  FIG. 3 , in module socket  20 , module fixing post  22  is provided, which has notch  23  for fixing memory module  10  to module socket  20 , in addition to a plurality of pins  21 . 
         [0046]    In installing memory module  10  to module socket  20 , pin  21  is inserted into through hole  14 , and module fixing post  22  is inserted into module fixing hole  15 . Module fixing hole  15  and notch  23  then engage with each other for fixing memory module  10  to module socket  20 . 
         [0047]    In addition, the length of pin  21  and the number of notches  23  provided in individual module fixing posts  22  are determined depending on the number of memory modules  10  to be installed to module socket  20 .  FIG. 3  shows the configuration in which installing two memory modules  10 . 
         [0000]    4. Method of Contacting Pin  21  with Through Hole  14   
         [0048]    Next, a method of contacting pin  21  with the inner wall of through hole  14  will be described with reference to  FIGS. 4 to 7 . 
         [0049]    In the example shown in  FIG. 4 , in installing memory module  10  to module socket  20 , a lateral pressure applied to module board  12  causes pin  21  to bend in order to bring pin  21  into contact with the inner wall of through hole  14 . 
         [0050]    In the example shown in  FIG. 5 , pin  21  itself is bent in advance, and a lateral pressure applied to module board  12  causes pin  21  to come into contact with the inner wall of through hole  14  when installing memory module  10  to module socket  20 . 
         [0051]    In the example shown in  FIG. 6 , pin  21  is soldered to through hole  14  with solder  41  so as to bring pin  21  into contact with the inner wall of through hole  14 . 
         [0052]    In the example shown in  FIG. 7 , metal contact member  42  in a triangular pyramid having a movable portion is attached to pin  21  so as to bring pin  21  into contact with the inner wall of through hole  14  via contact member  42  by a downward pressure applied to module board  12  when installing memory module  10  to module socket  20 . 
       5. Method of Applying a Lateral Pressure on Module Board  12   
       [0053]    Next, for the method of applying a lateral pressure to memory module  10  with reference to  FIGS. 4 and 5 , a method of applying a lateral pressure to individual module boards  12  in different directions will be described more specifically. 
         [0054]    For a means for applying a lateral pressure to individual module boards  12  in different directions, consideration is given to such a configuration in which a spring or the like is used. 
         [0055]    In contrast to this, as shown in  FIG. 8 , it is possible to implement the foregoing pressure applying means in which module fixing post  22  is bent in advance between the positions at which notches  23  are provided, and the positions of fixing memory modules  10  are shifted in individual module boards  12 . With such a simple configuration, it is possible to apply pressure to individual module boards  12  in different directions. 
         [0000]    6. Relationship between the Positions of Module Socket  20  and CPU  50   
         [0056]    Next, the relationship between the positions of module socket  20  and CPU  50  will be described with reference to  FIGS. 9 to 10 . 
         [0057]    In the example shown in  FIG. 9 , module socket  20  is mounted on the surface on which CPU  50  is also installed on motherboard  30 . 
         [0058]    In the example shown in  FIG. 10 , module socket  20  is mounted on the rear surface of motherboard  30  at the position opposite CPU  50  installed on the front surface of motherboard  30 . 
         [0059]    In this embodiment, the effect in which it is possible to arrange module socket  20  and CPU  50  in the position relationship as described with reference to  FIGS. 9 and 10  will be described in detail below in 7-1. 
       7. Effects of the Memory System According to This Embodiment 
     7-1. First Effect 
       [0060]    According to this embodiment, module socket  20  is a pin socket having a plurality of pins  21  two-dimensionally arranged, the pin socket is mounted in such a way that a plurality of pins  21  are vertically erected with respect to motherboard  30 , and a plurality of through holes  14  are arranged on module board  12  of memory module  10 , into which a plurality of pins  21  are individually inserted. 
         [0061]    With this configuration, there is obtained a first effect in which it is possible to increase the number of memory modules  10  to be installed with no increase in the area of motherboard  30  and in the bus length between CPU  50  and memory module  10 . The first effect will be described in detail below with reference to  FIGS. 11A to 11C . In addition,  FIG. 11A  shows the typical configuration of a memory system studied by the inventor.  FIG. 11B  shows the configuration of the memory system according to the present invention shown in  FIG. 9 .  FIG. 11C  shows the configuration of the memory system according to the present invention shown in  FIG. 10 . 
         [0062]    As shown in  FIG. 11A , in the typical memory system, the form of module socket  200 , into which memory module  100  is installed, is such that the module board is vertically installed on motherboard  30 . Thus, in the case of increasing the number of memory module  100  to be installed, the number of module sockets  200  is increased correspondingly, resulting in an increase in the area of motherboard  30 . Moreover, limitations are placed on the thickness of module socket  200  or on the wires or the like around module socket  200 , so that it is difficult to arrange individual module sockets  200  to be close to each other, and the length of bus wire  60  (simply referred to as the bus length) between CPU  50  and memory module  100  depends on the position at which module socket  200  is placed. 
         [0063]    In contrast to this, as shown in  FIGS. 11B and 11C , in the memory system according to the present invention, it is possible to install memory modules  10  to module socket  20  as memory modules  10  are installed horizontally to motherboard  30 . Furthermore, in the case of installing a plurality of memory modules  10  to module socket  20 , memory modules  10  are stacked on each other, and pins  21  of module socket  20  are inserted into through holes  14  in memory module  10 . 
         [0064]    As a result, because it is possible to install a plurality of memory modules  10  to single module socket  20 , it is possible to increase the number of memory modules  10  to be installed with no increase in the area of motherboard  30 . 
         [0065]    Moreover, because it is possible to install a plurality of memory modules  10  to single module socket  20 , intervals between the positions of a plurality of memory modules  10  do not suffer from the limitations on the position at which module socket  20  is placed, and it is possible to install a plurality of memory modules  10  at the positions much closer to CPU  50 . As a result, it is possible to increase the number of memory modules  10  to be installed with no increase in the bus length between CPU  50  and memory module  10 . 
         [0066]    Furthermore, as shown in  FIG. 11C , in the case where module socket  20  is mounted on the rear surface of motherboard  30  at the position opposite CPU  50  installed on the front surface of motherboard  30 , the bus length between CPU  50  and memory module  10  becomes the shortest. 
       7-2. Second Effect 
       [0067]    In addition, according to this embodiment, a plurality of memories  11  are installed around contact portion  13  so as to surround contact portion  13  on memory module  10 . 
         [0068]    As a result, there is obtained a second effect in which it is possible to shorten the stub length between contact portion  13  and memory  11 . The second effect will be described in detail below with reference to  FIGS. 12A ,  12 B,  13 A, and  13 B. Moreover,  FIG. 12A  shows the configuration of typical memory module (DDR 3: Double Data Rate 3)  100  studied by the inventor, and  FIG. 12B  shows the configuration of memory module (DDR3) 10 according to the present invention. Furthermore,  FIG. 13A  shows the configuration of typical memory module (DDR 2: Double Data Rate 2)  100  studied by the inventor, and  FIG. 13B  shows the configuration of memory module (DDR2) 10 according to the present invention. 
         [0069]    As shown in  FIGS. 12A to 12B , in the case of the DDR3, branching the CLK (clock) wire and the CA (command address) wire is not allowed. Thus, as shown in  FIG. 12A , in the typical DDR3, it is necessary to route a CLK wire and a CA wire from contact portion  130  to memory  11  located at one end of module board  120 . In contrast to this, as shown in  FIG. 12B , because this routing is unnecessary in the DDR3 according to the present invention, it is possible to shorten the stub length. 
         [0070]    On the other hand, as shown in  FIGS. 13A to 13B , in the case of the DDR2, branching the CLK wire and the CA wire is allowed. However, as shown in  FIG. 13A , in the typical DDR2, because a CLK wire and a CA wire from contact portion  130  have to be branched at only one place, the stub lengths to memories  11  located at both ends of module board  120  are lengthened. In contrast to this, as shown in  FIG. 13B , in the DDR2 according to the present invention, because a CLK wire and a CA wire can be branched at a plurality of places, it is possible to shorten the stub length by about a half. 
         [0071]    In addition, because the stub length of the DQ (data) wire and the stub length of the DQS (DQ strobe) wire are the same in both cases of the DDR2 and DDR3, the description is omitted. 
       7-3. Other Effects 
       [0072]    Moreover, according to this embodiment, because it is possible to install a plurality of memory modules  10  to single module socket  20 , there is obtained the effect in which it is possible to reduce the bus wiring region on motherboard  30 . Furthermore, because the dependency of the substrate length of module board  12  on the contact portion is eliminated (see contact portion  130  in  FIGS. 12A and 13A ), there is obtained the effect that the area of module board  12  is readily reduced. 
         [0073]    In addition, according to this embodiment, module socket  20  is a pin socket having a plurality of pins  21  two-dimensionally arranged, and a plurality of through holes  13  are arranged on module board  12  of memory module  10 , which individually correspond to a plurality of pins  21 . Thus, in the case of increasing the number of pins, it is possible to two-dimensionally increase the numbers of pins  21  and through holes  13 , and there is obtained the effect in which it is possible to control increases in the areas of motherboard  30  and module board  12 . 
         [0074]    It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.